Physicists Corentin Coulais, Vincenzo Vitelli, and collaborators solve a key robotics problem: emergent locomotion. Nicknamed the ‘odd wheel,’ their 12 motor-assembly adjusts its wiggling motion to move forward and navigate uphill, despite the fact it can’t perceive its terrain. “These are indeed behaviours you would not expect,” notes bioroboticist Auke Ijspeert. Future kinetic and structural applications include odd balls and odd walls.