A while ago Chris O’ Shea wrote about the Philips Simplicity Project, which had a number of mainly light-based inventions, several of them interactive.
One of them was this Drag and Draw idea - it’s basically a ‘bucket’ filled with light. Aimed at children, the child can dip a stick into the bucket and paint with light on the wall. I’m not really clear on the technology behind it, such as where the projection comes from (a laser projector in the bucket it seems - which doesn’t sound brilliantly safe for children’s eyes).
It looks to be a very lovely and intuitive interaction, especially when you can magically animate the drawing and reminds me a bit of Soda’s Moovl
Chris has found a video compilation online - I’m re-blogging it below: