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Class Information
Number: 434/331
Name: Education and demonstration > Question or problem eliciting response > Correctness of response indicated to examine by self-operating or examinee actuated means > By optical element (e.g., mirror, color filter, lens, etc.)
Description: Subject matter wherein the correctness of an examinee"s response is indicated by optical means.

Patents under this class:

Patent Number Title Of Patent Date Issued
8449302 Game piece with a selectively viewable hidden image May. 28, 2013
7055823 Cards Jun. 6, 2006
6053741 Flash card holder and learning method Apr. 25, 2000
5701696 Card holder Dec. 30, 1997
5618180 Method of teaching using a computer Apr. 8, 1997
5447439 Interactive story book using stickers and a method of teaching Sep. 5, 1995
5314197 Game apparatus May. 24, 1994
5295695 Method of coding gifts Mar. 22, 1994
5190298 Amusement devices Mar. 2, 1993
4891011 System for assisting the learning of a subject Jan. 2, 1990
4731023 Teaching system using prerecorded tape Mar. 15, 1988
RE32487 Binocular presentation of visual information Sep. 1, 1987
4674433 Correct answer displaying device for arithmetic practicing unit Jun. 23, 1987
4615682 Teaching system utilizing magnetic tape Oct. 7, 1986
4604065 Teaching or amusement apparatus Aug. 5, 1986
4521074 Binocular presentation of visual information Jun. 4, 1985
4286385 Color screen indicator Sep. 1, 1981

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