Sorry, just realised my last post might have come across as a bit harsh to non-spinner bots. Totally not my intention! I suppose I should have said I want something that I need to do more than just figure out how to drive it and build a drivetrain. I didn't want a flipper or axebot, as I need to beat a friend of mine's design (on paper) and I am not sure what he is planning. He did mention a shredder. I think he is thinking like one of those things you see on youtube that turns cars into confetti with the crushing / grinding teeth. And he is imaginative enough to be able to figure out how to build it too!