The Collaborative International Dictionary of English v.0.48:

Anorthoscope \A*nor"tho*scope\, n. [Gr. 'an priv. + 'orqo`s
   straight + -scope.] (Physics)
   An optical toy for producing amusing figures or pictures by
   means of two revolving disks, on one of which distorted
   figures are painted.
   [1913 Webster]