http://www.ministryoftype.co.uk/images/files/synth-type.jpg

The Meek FM Typographic Synthesizer enables direct and physical manipulation of letters via a controller. A cursor constantly redraws the type-face-specific shape of a selected letter on the screen and also functions like a play-head for sound output. Thus you can define transformations which get automatically applied to the whole font and simultaneously affect the character of the audio.
There have already been preceding versions of the Typographic Synthesizer without hardware which could be tried out on www.robmeek.com.