I tried to get the 2 colors shown in the picture by coloring all the icing light brown with cocoa, and then adding blue to half of it, but it didn't work because I bought all-natural food color, which turned out not to affect the color of the icing strongly enough. It might have tinted pure white icing a light blue, but the effect of the cocoa completely overwhelmed it.
For the teeth, I had hoped to find yogurt raisins in the bulk section of the same health food store where I got the food color, but they were out of stock, so I used slivered almonds instead. And B insisted that both the eye and nostril should be made of raisins. The leaf was satisfyingly easy - I simply cut off a leaf from our cycad tree outside! Even if cycads weren't part of the Plateosaurus' diet, they were around in the time of the dinosaurs, so it felt quite authentic. Here's the finished product: