use projection .. have say .. 20 wheels with letter shapes that rotate with a mechanical keyboard or again a set of parallel wheels , backlighted to a frosty piece of glass .. edit is simply rotate one of the wheels . did i miss the point ? :D
use projection .. have say .. 20 wheels with letter shapes that rotate with a mechanical keyboard or again a set of parallel wheels , backlighted to a frosty piece of glass .. edit is simply rotate one of the wheels . did i miss the point ? :D