Tell us about yourself!
Fun! Great that you're doing this with a "stock" xy rig so you can do an instructable. We built a custom rig like that in 2010. Lawrence even wrote a script to compensate for the sun's motion. That's a must if you're going to etch out complex designs. https://www.youtube.com/watch?v=-x1xiT70yXk Sadly this was long before I had a blog, so the build was never written up.
Blooms: Phi-Based Strobe Animated Sculptures
Build a cheap Car Seat Roller for Use at the Airport