My 3rd digital painting

Reference image:

Lesson learned: NEVER TRY TO FREEHAND CIRCLES WITH PERSPECTIVE

Speaking of perspective, I definitely didn't place my vanishing points right if you compare with the reference. Also the hole is noticeably offset from the center and too wide and the bottom and top aren't properly aligned. I think I'll try to redo this one sometime, now that I have a better idea of what I should and shouldn't do.

I think these posts might become more or less a regular thing (as regular as my whims are, i.e. not very).