INTP:
As a supposed engineering student, you might first imagine something as simple as a motor and a cam system. 2 DC motors with nubs on the shaft are all that are needed. The toys move very obviously like cars that are divided left side and right side wheel control.
The rest of you folks surprise me. Tsk.
Try reply #7
"It might be possible to drive each side with 1 motor and some mechanics."
And nobody +1'd Steiner's short film, Mechanical Principles.
If I but a button magnet on an axle that's perpendicular to the magnetic poles (the faces) and free to spin then wrapped 2 coils around that so they cross at/around the axles then powering one of those coils will cause the magnet to turn and align itself with that coil, and it will happen quick. Other coil gets the current, magnet will turn to align with that coil. Both coils result in a field that points to neither. That motor can be quite compact and may already be patented.