Skateboarding evolved from surfing when people combined surfboards with wheels to ride on land when the ocean was calm. Early skateboards were long banana-shaped boards or fish-tail shaped boards. The modern skateboard design was created with wheels in each corner. Key inventors included Rodney Mullen who invented the kickflip and Alan Ollie Gelfand who invented the ollie. Tony Hawk landed the first 900 degree turn, advancing tricks in skateboarding.