Challenge 30 is Seishi Kasumi’s “Mask of Ape”. It looks more like a monkey mask to me. The Japanese title of the model is “猿”, which can be monkey or ape, so I guess it can be either.
This is a pretty nifty 3D model. I initially didn’t like it too much, but it grew on me. The first time, I used rigid paper to hold the 3D shape, and, the second time, I used the flimsy paper I usually use. Both times I drew in a lot of the lines to make it easier.
This first time I drew in the lines with red for mountain folds and blue for valley folds.
Since I was better at keeping track the second time, I just used yellow highlighter to draw in lines. It lit up when the camera flash hit it for a neat effect. I hope it works the same way with a black light.