Pixar in a Box 2

Today we continued our study of Pixar, and found out more about how this amazing company is able to create such fun and cool new virtual worlds for us every time they release a new movie.
Lesson 2: Crowds
When the designers were planning Wall-e, they wanted him to go from a world where there was only one robot - himself on Earth - to a place where there were hundreds of different robots, all with their own jobs and purposes.
The designers were tasked with creating all these different robots, but instead of inventing a thousand different robots form scratch, they simply used the branch of mathematics known as "combinatorics" to create a few different heads, a few bodies, a few arms, etc, and mixed and matched them.
We also had a design task to carry out or ourselves. The challenge was to create 1000 different dinosaurs by using a limited number of body parts (head, tail, arms, legs and body) - preferably fewer than 25. In the end we worked out that 21 or 24 different body parts is the answer, and we designed what they might look like.
Here's the maths:
2 x 5 x 10 x 5 x 2 = 1000 (24 body parts)
or
4 x 5 x 5 x 2 x 5 = 1000 (21 body parts)