This was last night's attempt at the 20-minute challenge. Now experienced, I limited myself to five items--three pears, a copper plate, and a woven leather place mat; I set them under a single overhead light and chose conte pastel pencils because the colors are easy to identify. Using the microwave timer (no ticking) very little was recognizable at 20 minutes. I kept going--for a total of 45 minutes, even with the elimination of the place mat!
I will try the challenge again and I almost have a plan: I'll stick with the pastel pencils and tackle maybe one lemon on a white paper plate (no reflections). Speedy is not my nickname but this is fun.