Hugh says he started by gutting the inside of the iMac's base, removing all components. Next, he removed the display and cut the back side of it into a flower shape, making sure to keep the Apple logo intact. Last, he connected a ceiling light to the top of the arm, ran wiring through the base, and added a power switch.
All in all, this is a brilliant do-it-yourself project that takes recycling to a whole new level. More photos can be found in the MacRumors forums.