One of the most challenging pieces that I've created would be a piece I named Absolute Uncertainty. I used a three point perspective in this painting and had to actually build an apparatus and attach it to the wall of the studio I was working in. See below images.
Showing How I Created a Three Point Perspective in my Studio
Left Arm
Right Arm
Bottom Arm
Zoom in!
I have this feature so you can see a closer view of the artwork. Put your mouse over the painting below and enjoy!