From GameBrew - a wiki dedicated to Video Game Homebrew.
A stereogram drawing application for the Nintendo DS. Draw-stereo is a toy which allows the creation of stereograms on the Nintendo DS.
The DS screens are spaced appropriately for cross-eye stereogram viewing. For best results, use in a darkened room, and hold the DS at a comfortable distance for drawing (18" or so).
Hold the DS like a book. The illusion can be quite effective. Enjoy.
Up/Down - Pen elevation +/- 1px
A/B/X/Y - Reset elevation
Select/Start - Clear screens
L/R - Swap screens (reverses depth)