3800443

Information

• Patent Grant
• 3800443

• References
• Source

• Patent Number

  3,800,443

• Date Filed

  Not available

• Date Issued

  Tuesday, April 2, 1974
  50 years ago

• CPC

  • G09B17/04 - for increasing the rate of reading Reading rate control
  • Y10S273/31 - Undulated surface

• US Classifications

  • 434 - Education and demonstration
  • 273 - Amusement devices: games
  • 446 - Amusement devices: toys