I made a few improvements to the Cat3rpillar:

• Changed the looks, especially its head.
• Using wheels in the rear for better grip when pushing the bot forward.
• Rear wheels turn only in forward direction to minimize grip when rear is going forward and maximize grip when pushing the robot forward.
• Steering mechanism, so the CAT3RPILLAR can change its direction.</li>

Program is written with the iPadapp, steering is possible by using the EV3 remote.

Video: