I tried making a Voronoi diagram in as little blocks as possible. This is what I got. If slow, use turbowarp: https://turbowarp.org/1051187087?turbo You should probably use turbo mode (shift click the green flag), as the rendering takes a while.
Thanks so much to @HDGraphics for the idea of how to get rid of 3 blocks, and generating 1000 circle costumes for me! I got the general idea of how this could work from this project: https://scratch.mit.edu/projects/697926016/ Technically, this is 28 blocks, but I could get rid of the code in the backdrop, and it would still function the same, it just wouldn't generate a new diagram each time it's run.