The Siftables guys demoed a pouring interface for color mixing, among other things: http://www.ted.com/talks/david_merrill_demos_siftables_the_smart_blocks.html

The Siftables guys demoed a pouring interface for color mixing, among other things: http://www.ted.com/talks/david_merrill_demos_siftables_the_smart_blocks.html http://www.ted.com/talks/david_merrill_demos_siftables_the_s... Not sure if that feature made it into the commercially available version, but they definitely still have the proximity features, which are pretty cool: https://www.sifteo.com https://www.sifteo.com