CmdrTaco from the toys-to-want-to-have dept.
edpin writes "CNN is reporting this new mouse that works without a surface. You hold the device in your hand and tilt it to where on screen you want it to go. It uses a similar technique to "rock and scroll" developed by Compaq (now HP) a while ago."
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"