Origami envelope

Abstract

A method of forming an origami envelope from a sheet of material is provided. The method comprises folding the sheet of material to create at least five fold lines. The origami envelope is formed from the sheet of material comprising at least five steps. In some embodiments, the method comprises an optional folding step. The optional folding step includes folding the sheet width wise to create an optional crease line.

Description

TECHNICAL FIELD

This invention relates to envelopes, and methods of making same.

BACKGROUND

Numerous envelopes are used on a daily basis, to deliver messages or objects such as letters, notes, cards, gift cards, coupons, promotional materials, and money from one person to another. Conventional envelopes can be environmentally wasteful and costly because such envelopes are typically limited to a one-time use once the envelope has been printed on, or is sealed.

Origami envelopes (envelopes made from a folded piece of paper) can be substituted for conventional envelopes. However, existing origami envelopes are typically folded in a way such that the folded envelopes are oddly-shaped and sized and/or do not resemble conventional envelopes in shape or function. Such designs of folded envelopes are impractical since these oddly-shaped and sized envelopes may be more prone to being lost in the mail, and/or may not hold objects which are not easily foldable, such as cash. In addition, prior art origami envelopes are typically folded using square-sized paper (i.e. where the width and the length of the paper are substantially equal) which is typically less readily available than other sizes of paper. In addition, some prior art origami envelopes may be constructed from folding irregular shaped sheets of paper (e.g., with protruding sections and cut-outs). In such cases, an operator must first manually trace and then cut out the sheet of paper in accordance with a template prior to folding. This can be very time-consuming.

There is a general desire for apparatus and methods that address at least some of the aforementioned problems.

The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

SUMMARY

One aspect relates to a method of forming an origami envelope. Another aspect relates to an origami envelope formed by such method. The origami envelope is folded using a sheet of material. The sheet of material has a top right corner, a top left corner, a bottom right corner, and a bottom left corner, a top edge extending between the top right corner and the top left corner, a bottom edge opposite of the top edge, extending between the bottom right corner and the bottom left corner, and a first and second side extending between the top and bottom edges, the first side extending between the top left corner and the bottom left corner, and the second side opposite of the first side, extending between the top right corner and the bottom right corner. The sheet of material is first oriented such that the top and bottom edges extend width wise, and the first and second sides extend length wise. The sheet of material is folded to create at least five fold lines. The at least five fold lines comprises: a first fold line extending diagonally between a first midpoint positioned at one of the first and second sides and a first point positioned at one of the top and bottom edges, a second fold line extending diagonally between the first midpoint and a second point positioned at the edge that is opposite of the edge having the first point, a third fold line extending diagonally between a second midpoint and a third point positioned adjacent to one of the first and second points, a fourth fold line extending diagonally between one of the top corners and a fourth point positioned adjacent to the second midpoint, and a fifth fold line extending diagonally between the first or second point that is positioned at the top edge and a fifth point positioned adjacent to the second midpoint, wherein the second midpoint is positioned between the fifth point and the fourth point.

In some embodiments, the method of forming the origami envelope comprises at least five steps. The at least five steps comprises: a first step of folding the sheet of material along the first fold line to create a first substantially triangular structure, a second step of folding the sheet of material along the second fold line to create a second substantially triangular structure, a third step of folding the sheet of material along the third fold line to create a quadrilateral structure, a fourth step of folding the sheet of material along the fourth fold line to create a top and a bottom layer and a third substantially triangular structure extending from the top layer, and a fifth step of folding the sheet of material along the fifth fold line to extend the third substantially triangular structure from the top layer over to the bottom layer.

In some embodiments, the method of forming the origami envelope further comprises folding the sheet width wise to create an optional crease line extending between the first and second midpoints.

Another aspect relates to an origami envelope constructed from a sheet of material having a top edge extending between a top left corner and a top right corner, a bottom edge opposite of the top edge, extending between a bottom left corner and a bottom right corner, a first side extending between the top left corner and the bottom left corner, and a second side opposite of the first side, extending between the top right corner and the bottom right corner. The origami envelope comprises: a top envelope side and a bottom envelope side opposite of the top envelope side, a left envelope side and a right envelope side opposite of the left envelope side, a top layer having a front surface and a back surface opposite of the front surface, and a bottom layer having an exterior side and an interior side opposite of the exterior side, wherein the back surface of the top layer is in contact with the interior side of the bottom layer, and wherein the top layer extends to the exterior side of the bottom layer over a portion of the top envelope side and wherein the exterior side of the bottom layer comprises a triangular closure flap.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF DRAWINGS

Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

FIG. 1 is a top view of an unfolded configuration of an origami envelope showing the fold lines in accordance with an embodiment of the invention.

FIG. 2 illustrates an optional step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 3 illustrates a first step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 4 illustrates a second step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 5 illustrates a third step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 6 illustrates a fourth step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 7 illustrates a fifth step in construction of an origami envelope in accordance with an embodiment of the invention.

FIG. 8 is a top front view of a folded configuration of an origami envelope in accordance with an embodiment of the invention.

FIG. 9 is a top back view of a folded configuration of an origami envelope in accordance with an embodiment of the invention.

DESCRIPTION

Throughout the following description, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

FIG. 1 illustrates an unfolded sheet 10 which may be folded into an origami envelope 11 according to a particular embodiment. Any suitable type of paper or any foldable materials such as plastic, foil, fabric, cardboard, cloth, napkin, and the like may be used as sheet 10.

Sheet 10 has a rectangular shape defined by a set of top corners 16, 18, and a set of bottom corners 20, 22 positioned opposite of their respective top corners 16, 18. In the illustrated embodiment, sheet 10 may comprise a width W which is shorter than a length L. Width W is defined as a top edge 10A or a bottom edge 10B. Top edge 10A extends between top corners 16, 18. Bottom edge 10B, positioned opposite of top edge 10A, extends between bottom corners 20, 22. Length L is defined as a first side 10C or a second side 10D. First side 10C extends between top corner 16 and bottom corner 20. Second side 10D, positioned opposite of first side 10C, extends between top corner 18 and bottom corner 22.

In some embodiments, sheet 10 may have dimensions of a standard letter-size paper (i.e., 8½ by 11 inches, or 216 mm by 279 mm). In some embodiments, sheet 10 may have dimensions of a A4-sized paper (i.e. 8½ by 14 inches, or 210 mm by 297 mm). However, sheet 10 may have different dimensions in other embodiments. For example, sheet 10 may comprise a square or near-square shape, wherein a length is equal to or approximately equal to a width.

In the illustrated embodiment, sheet 10 has six fold lines 24, 30, 34, 38, 42, and 46 to make the origami envelope. An optional crease line 24 intersecting a center point 14 of sheet 10, extends substantially horizontally from a midpoint between top left corner 16 and its respective bottom left corner 20 (i.e. a first midpoint 26) to a midpoint between top right corner 18 and its respective bottom right corner 22 (i.e. a second midpoint 28), such that optional crease line 24 extends substantially parallel to the width W of sheet 10.

A first fold line 30 extends diagonally from the first midpoint 26 to a point positioned off-centered from the center point 14 along top edge 10A (i.e. a top point 36). In the illustrated embodiment, top point 36 is located more proximate to second side 10D than first side 10C. Top point 36 is located at approximately ⅔ of the width W of sheet 10 from first side 10C and approximately ⅓ of the width W of sheet 10 from second side 10D.

A second fold line 34 extends diagonally from the first midpoint 26 to a point positioned along bottom edge 10B opposite of the top point 36 (i.e. a first bottom point 32). Thus, similar to top point 36, first bottom point 32 is located approximately ⅔ of the width W of sheet 10 from first side 10C and approximately ⅓ of the width W of sheet 10 from second side 10D. Additionally, second fold line 34 and first fold line 30 are mirror images of each other having an axis of symmetry which extends along optional crease line 24.

A third fold line 38 extends diagonally from the second midpoint 28 to a point positioned off-centered from the center point 14 along bottom edge 10B, adjacent to the first bottom point 32, and is located more proximate to the first side 10C than the second side 10D (i.e. a second bottom point 40). In some embodiments, second bottom point 40 is located at approximately ⅓ of the width W of sheet 10 from first side 10C and approximately ⅔ of the width W of sheet 10 from second side 10D. Additionally, third fold line 38 is positioned substantially parallel to the first fold line 30 and perpendicular to second fold line 34.

A fourth fold line 42 extends from top corner 16 to a point off-centered from center point 14 along second side 10D, and which such point is located more proximate to the bottom edge 10B than the top edge 10A (i.e. a first right point 44). First right point 44 is located at approximately 0.77 of the length L of sheet 10 extending from top edge 10A, and approximately 0.23 of the length L of sheet 10 extending from bottom edge 10B. Additionally, fourth fold line 42 is positioned substantially parallel to third fold line 34 and perpendicular to first fold line 30 and third fold line 38.

A fifth fold line 46 extends from top point 36 to a point off-centered from the center point 14 along the second side 10D, located adjacent to first right point 44 but more proximate to the top edge 10A than the bottom edge 10B (i.e. a second right point 48). Second right point 48 is located at approximately 0.27 of the length L of sheet 10 from top edge 10A, and approximately 0.73 of the length L of sheet 10 from bottom edge 10B. Additionally, fifth fold line 46 is positioned substantially parallel to second fold line 34 and fourth fold line 42 and perpendicular to first fold line 30 and third fold line 38.

In some embodiments, sheet 10 includes only five fold lines 30, 34, 38, 42, and 46. In other words, optional crease line 24 is optional. Optional crease line 24 may merely be a pre-crease fold line. The pre-crease fold line is not required for the folding on the final product, but may be beneficial for aligning the other folds.

In FIG. 1, sheet 10 is shown with an inside surface 12 of sheet 10 facing up. Outer surface 13 (not seen in FIG. 1 but shown in FIGS. 8 and 9) is on the opposite side of sheet 10 and is facing down. Inside surface 12 of sheet 10 is not visible when envelope 11 is in its folded configuration. In some embodiments, messages may be written or printed directly on inside surface 12 so that addresses and stamps may be placed on an outer surface 13 when envelope 11 is in its folded configuration as shown in FIG. 8. In some embodiments, a separate piece of paper containing the message may be inserted into envelope 11 so that envelope 11 may be used as a folder or compartment. In some embodiments, objects such as greeting cards, gift cards, business cards and the like may be inserted into envelope 11. In some embodiments, envelope 11 may comprise both a printed message written on inside surface 12 and a separate message and/or object inserted into envelope 11.

The size of sheet 10 determines the size of the folded configuration of origami envelope 11. The object that could fit into origami envelope 11 would thus depend on the size of sheet 10. For example, if one wishes to insert a standard gift card (i.e. having dimensions of about 3⅜ by 2⅛ inches, or 85.725 mm by 53.975 mm) into origami envelope 11, sheet 10 having dimensions of approximately 6½ by 5 inches (165.1 mm by 127 mm) may be used. Accordingly, the size of sheet 10 may be customized to accommodate the different sizes of objects that are to be inserted into envelope 11.

FIGS. 2 to 9 illustrate the steps in making origami envelope 11. Origami envelope 11 may be constructed by five or six folding actions. To construct origami envelope 11, sheet 10 must first be oriented such that the top 10A and bottom 10B edges extend along the width W of the sheet 10, and the first 10C and second 10D sides extend along the length L of the sheet 10. FIG. 2 illustrates an optional step. The optional step is a pre-crease operation (i.e. fold, crease, and unfold) to generate optional crease line 24, which optional crease line 24 extends substantially parallel to the width W of sheet 10. This is done by folding sheet 10 in half width wise, such that top corners 16 and 18 are substantially aligned with their respective bottom corners 20 and 22. Folding sheet 10 is creased, and then unfolded.

Referring to FIG. 3, a first step in the construction of origami envelope 11 is shown. In this step, a first corner is folded down diagonally along first fold line 30 to meet optional crease line 24. This creates a first triangle 31 (as best seen in FIG. 4). In the illustrated embodiment, top left corner 16 is folded down to form first triangle 31. Thus, first triangle 31 is folded from a portion of first side 10C of sheet 10. This is not mandatory, however. In some embodiments, the first triangle 31 may be folded from a portion of second side 10D. In such embodiment, first fold line 30 may be created by folding down top right corner 18 to meet optional crease line 24.

FIG. 4 illustrates a second step in the construction of origami envelope 11. In this step, a second triangle 33 is created by folding a second corner diagonally to meet optional crease line 24. In the illustrated embodiment, the second triangle 33 is created by folding up bottom left corner 20 diagonally along second fold line 34 to meet optional crease line 24 so that bottom left corner 20 is positioned adjacent to top left corner 16. Second triangle 33 and first triangle 31 are mirror images of each other having an axis of symmetry extending along optional crease line 24. In such embodiment, the two triangles are formed by folding the respective top and bottom corners that are positioned at the same side of sheet 10 in steps 2 and 3 (i.e. folding top left corner 16 and bottom left corner 20 or folding top right corner 18 and bottom right corner 22). In some embodiments, second fold line 34 may be positioned on the right side of sheet 10. In such embodiment, second fold line 34 may be created by folding up bottom right corner 22 to meet optional crease line 24.

In some embodiments, folding along second fold line 34 can occur before folding along first fold line 30. In other words, step 2 as illustrated in FIG. 4 may occur before step 1 as illustrated in FIG. 3.

In alternate embodiments, first 31 and second 33 triangles are not mirror images of each other as illustrated. In such embodiments, first 31 and second 33 triangles are formed by folding top and bottom corners that are positioned at opposite sides of sheet 10 (i.e. folding top left corner 16 and bottom right corner 22 or folding top right corner 18 and bottom left corner 20 in steps 1 and 2).

FIG. 5 illustrates a third step in the construction of origami envelope 11. In this step, a third corner is folded up or down to meet optional crease line 24 to form a quadrilateral 35 and triangular layer 36. In the illustrated embodiment, bottom right corner 22 is folded up diagonally along third fold line 38 subsequent to folding top left corner 16 down diagonally along first fold line 30 and bottom left corner 20 up diagonally along second fold line 34 to meet optional crease line 24 in steps 1 and 2. Following these particular folds, triangular layer 36 is positioned having a corner at first midpoint 26 (as best seen in FIG. 6). However, any third corner may be folded up or down. For example, for the configuration of FIG. 5, top right corner 18 may alternatively be folded down to meet optional crease line 24. The third corner may be any corner which has not been folded down or up to meet optional crease line 24 in the previous steps; as such, the third corner may be any of top corners 16 and 18, or bottom corners 20 and 22. The position of triangular layer 36 changes depending on which of the three corners of sheet 10 are folded in steps 1 to 3. For example, for the embodiment which top left corner 16 and bottom right corner 22 of sheet 10 are folded down and up along first fold line 30 and third fold line 38 respectively to meet optional crease line 24 in steps 1 and 2 (in any order) and bottom left corner 20 is folded up along second fold line 34 to meet optional crease line 24 in step 3, triangular layer 36 is positioned having a corner at second midpoint 28.

FIG. 6 illustrates a fourth step in the construction of origami envelope 11. In step 4, the bottom of the folded product formed by second fold line 34 is folded up to meet line 51 by folding along fourth fold line 42. In other words, first midpoint 26 and fold point 41 is folded up to meet left top point 36 and point 52, respectively. This fourth folding action produces a top and bottom layer of envelope 11, and a substantially triangular structure referred to as a closure flap 53. Top layer of envelope 11 includes a front surface (as seen in FIG. 8 which shows the front view of envelope 11) and a back surface opposite of the front surface (not shown). Bottom layer of envelope 11 includes an exterior side (as seen in FIG. 9 which shows the back view of envelope 11) and an interior side opposite of the exterior side (not shown). The back surface of the top layer is in contact with the interior side of the bottom layer when the top and bottom layers of envelope 11 are formed in the fourth step.

FIG. 7 illustrates a fifth step in the construction of origami envelope 11. Step 5 involves folding closure flap 53 down along sixth fold line 46 to produce a finished origami envelope 11, which is illustrated in FIG. 8 (showing a front view of origami envelope 11) and FIG. 9 (showing a back view of origami envelope 11). Fifth fold line 46 substantially aligns with line 51. Closure flap 53 may be optionally sealed to secure the contents in origami envelope 11 using adhesive tape, glue, staples, a sticker and the like.

Referring to FIG. 8 which shows the front view of origami envelope 11, origami envelope 11 comprises a top envelope side 54A, a bottom envelope side 54B, a left envelope side 54C and a right envelope side 54D. In the illustrated embodiment, the side which extends along the top envelope side 54A and the bottom envelope side 54B is length L₁₁, and the side which extends along the left envelope side 54C and the right envelope side 54D is width W₁₁. Length L₁₁ is greater than a width W₁₁. In some embodiments, width W₁₁ is approximately ⅔ of length L₁₁.

In the illustrated embodiment, origami envelope 11 comprises a triangle 57 positioned at a top left corner of origami envelope 11. Triangle 57 comprises two substantially equal length sides 59A and 59B perpendicularly positioned to form a right angle, and a side 59C having a length longer than 59A and 59B, positioned opposite of the right angle. In some embodiments, side 59A may extend along a portion of top envelope side 54A, and side 59B may extend along a portion of left envelope side 54C. In alternative embodiments, side 59A may extend along a portion of top envelope side 54A, and side 59B may extend along a portion of right envelope side 54D.

In some embodiments, side 59C of origami envelope 11 may be constructed from a portion of length L of sheet 10. Side 59C of envelope 11 may be constructed from the portion of second side 10D which extends between second midpoint 28 and second right point 48.

In some embodiments, triangle 57 is created by extending the top layer of envelope 11 to the bottom layer over a portion of the top envelope side 54A. In some embodiments, a ratio between the portion of the top envelope side and the top envelope side is approximately 0.65 to 0.75. In such embodiments, a ratio between side 59A of triangle 57 and the top envelope side 54A is thus between 0.25 to 0.35.

Referring to FIG. 9 which shows a back view of origami envelope 11, as discussed in relation to FIG. 7, origami envelope 11 comprises closure flap 53. Closure flap 53 comprises a triangle having two substantially equal length sides 62A and 62B perpendicularly disposed to form a right angle at top right corner 18, and a side 62C having a length longer than 62A and 62B positioned opposite of the right angle.

In some embodiments, side 62B of envelope 11 may be constructed from a portion of length L of sheet 10. Side 62B may be constructed from the portion of second side 10D which extends between second right point 48 and top right corner 18. In some embodiments, side 62A may be constructed from a portion of width W of sheet 10. Side 62A may be constructed from the portion of top edge 10A which extends between top right corner 18 and top point 36.

In some embodiments, sheet 10 is not pre-creased and one would be required to create fold lines 24, 30, 34, 38, 42, and 46 or fold lines 30, 34, 38, 42, and 46 manually to produce origami envelope 11. In some embodiments, sheet 10 may be pre-creased with folds lines 24, 30, 34, 38, 42, and 46 or fold lines 30, 34, 38, 42, and 46 by a machine.

In some embodiments, a printed message may first be written on inside surface 12 of sheet 10 prior to the construction of origami envelope 11 according to the five or six steps that are illustrated in FIGS. 2 to 9. First triangle 31, second triangle 33 and quadrilateral 35 are concealed within envelope 11 and thus referring to FIGS. 4 to 6, additional messages may be printed on first triangle 31, second triangle 33, and/or quadrilateral 35 in steps 2, 3, and 4 respectively.

In some embodiments, objects such as gift cards, cards, letters, and the like may be inserted into envelope 11 during which the envelope 11 is being constructed. For example, such objects may be inserted into envelope 11 between steps 3 and 4 (see FIGS. 5 and 6) when the compartment of envelope 11 has been constructed. The compartment of envelope 11 includes opposing edges 54A, 54B and opposing sides 54C, 54D (as shown in FIGS. 8 and 9).

The contents inside envelope 11 may be secured by attaching closure flap 53 onto envelope 11. Closure flap 53 is depicted in FIG. 9. Closure flap 53 may be attached to envelope 11 by using glue, tape, a sticker, staples and the like. In addition, the front of the envelope, as best seen in FIG. 8, can include the name and/or address of the recipient, as well as a mailing stamp.

To access the contents within origami envelope 11, a recipient can lift closure flap 53 (i.e. unfold fold line 46), and unfold each of fold lines 42, 34, 30 and 38 to return to the unfolded configuration, i.e. unfolded sheet 10 as shown in FIG. 1. In other words, one can reverse each of the folding steps 1-5 as illustrated in FIGS. 3-7 to unfold envelope 11.

Origami envelope 11 has many advantages over existing origami envelopes. Origami envelope 11 can be substituted for conventional envelopes. Unlike prior art origami envelopes which are often constructed using irregular shaped paper or the conventional square sized origami paper, origami envelope 11 can be constructed using paper sizes which are readily available, in particular, rectangular-dimensioned paper such as legal or A4-sized paper. In addition, origami envelope 11 can be easily constructed by as few as five folding actions, without using additional tools such as scissors.

While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Claims

1. A method of forming an origami envelope comprising: providing a sheet of material having a top right corner, a top left corner, a bottom right corner, and a bottom left corner, a top edge extending between the top right corner and the top left corner, a bottom edge opposite of the top edge, extending between the bottom right corner and the bottom left corner, and a first and second side extending between the top and bottom edges, the first side extending between the top left corner and the bottom left corner, and the second side opposite of the first side, extending between the top right corner and the bottom right corner;orienting the sheet of material such that the top and bottom edges extend width wise, and the first and second sides extend length wise;folding the sheet of material to create at least five fold lines, the at least five fold lines comprises: a first fold line extending diagonally between a first midpoint positioned at one of the first and second sides and a first point positioned at one of the top and bottom edges;a second fold line extending diagonally between the first midpoint and a second point positioned at the edge that is opposite of the edge having the first point;a third fold line extending diagonally between a second midpoint positioned at a side opposite to the first midpoint and a third point positioned adjacent to one of the first and second points;a fourth fold line extending diagonally between one of the top corners and a fourth point positioned adjacent to the second midpoint; anda fifth fold line extending diagonally between the first or second point that is positioned at the top edge and a fifth point positioned adjacent to the second midpoint, wherein the second midpoint is positioned between the fifth point and the fourth point, andfolding the sheet of material to form the origami envelope comprising at least five steps, wherein the at least five steps comprising:a first step of folding the sheet of material along the first fold line to create a first substantially triangular structure;a second step of folding the sheet of material along the second fold line to create a second substantially triangular structure;a third step of folding the sheet of material along the third fold line to create a quadrilateral structure;a fourth step of folding the sheet of material along the fourth fold line to create a top and a bottom layer and a third substantially triangular structure extending from the top layer; anda fifth step of folding the sheet of material along the fifth fold line to extend the third substantially triangular structure from the top layer over to the bottom layer.

2. The method of claim 1, wherein the first point and the second point are located more proximate to one of the first and second sides than the other of the first and second sides and the third point is located more proximate to the other one of the first and second sides than the one of the first and second sides.

3. The method of claim 1, wherein the first, second and third triangular structures have right angles, the right angles positioned at the top and/or bottom corners of the sheet, and located opposite of the first and second and fifth fold lines, respectively.

4. The method of claim 1, further comprising folding the sheet width wise to create an optional crease line extending between the first and second midpoints.

5. The method of claim 1, wherein the sheet is rectangular in shape and is defined by a width and a length, wherein the width is shorter than the length.

6. The method of claim 1, wherein a ratio between the width of the sheet and the length of the sheet is between approximately 0.5:1 to approximately 0.75:1.

7. The method of claim 1, wherein the sheet of material comprises paper.

8. The method of claim 1, wherein the third substantially triangular structure comprises a closure flap, removably secured to a body of the origami envelope.