Its real name is in fact I/O Brush, which was released by MIT Media Lab last year.
Uh, we know very well that it is out of date to talk about it now, so please don't shout "toooooooooooold" at us.
If you have not heard of this magic brush before, our suggestion is to watch the video first. Because its effect is so novel that if we explain it beforehand, it won't be fun anymore.
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