In AOTC, R4 is an astromech droid that is all head and no body. It is literally attached to the starfighter that Obi Wan flew. In the original concept, LF was going to have it where R4 can pop out of its socket, and walk around with little legs/arms. However the idea was cut. Good thing to. That might have been stupid, kind of like Jar Jar.
Don't know if I'm right, so passing on a question