SOLVED. Adult Scifi/ Fantasy, Short story. Main character constructs magic shapes. Read 2012-2016. [s]

[Michael]

I read this short story online (or it may have been an online audiobook) sometime between 2012 and 2016.

It was set in modern times, was written in English, and the main character is a man who has the ability to draw new shapes and polygons with strange effects. He lives alone and uses some natural instinct to invent them.

The mysterious group he works for keeps him happy by bringing anything he asks for. He writes requests on white board, and in the morning they leave them for him. Normally it's just food and mundane things, but at one point he asks for a Rembrandt painting (I think?) to test their limits and they procure it for him easily.

I don't remember how it ends and it's driving me crazy, haha.

[Michael]

Hot dog! You got it in one. Thank you so much, that is it!