Why only two wheels?

When this project was born, I immediately asked me what kind of traction.
A real cat would have four legs, but implement them properly, ensuring proper locomotion, would require a very careful construction and a considerable difficulty in achieving movements.
But since I wanted to make it work and I did not want to stop by excessive technical problems, I decided to reduce everything to a system with two wheels and a jockey wheel.

After all, my sources of inspiration were two:
My cat "Ciccio" and K9, the faithful and robotic friend of Doctor Who.

Make It Simple, Stupid!

:)