[TOMT] [YouTube Video] Short animated video about humanoid characters drawing squares

I remember watching a short video on YT, I think around 5 years ago. It was about humanoid characters drawing squares in a set rhythm, with one character having problems with their hand becoming unsteady/having its own mind, resulting in the character scribbling over a whole room they were in.

I think it was completely grayscale. The characters were blank: fully white, no faces, no hair, etc.