cant find this canvas anywhere for my dad

Basically, he saw this set in a gallery in copenhagen that 'self erases' itself after a few minutes. I believe it was some sort of water colour canvas that would fade away and it was a tool of some sort to help practice painting. he's asked me for this for christmas and in typical dad fashion has given me little to go off of! i've seen the sort of thing he means before but I can't find it online anywhere! this is a long shot but if anyone has any idea what im talking about please send me a link!! Thanks!