palinode                a poem in which the poet retracts something
                        said in an earlier poem.
pseudoscope             an optical device for producing a depth-reversed image.
cassation               cancellation or reversal; a type of
                        18th-century instrumental suite.
tain                    tin foil used to silver mirrors.
librate                 to balance; to oscillate from side to side.
equivoque               an ambiguous expression; a play on words;
                        double meaning.
squeg                   (of an electronic circuit) to oscillate
                        between zero and a certain maximum value. 
diadochokinesia         the (normal) ability to execute fast 
                        alternating movement.