"The new TX4 model is an improvement of the older XT4 model. TX4 stands for "Tougher XT4 with 4 spinning blades". The TX4 models are easily reprogrammed to fit all your needs, from slicing vegetables to taking over the galaxy. "
The only way I wanted to revamp XT4 was by giving him a spinning function. Because all cartoon robots that have sawblades can do that, right?
Those panels at his head were added to give his body build an "X" shape with the spinning function at the intersection.