Probably some time around when the first twintip was nivented- in the 1930's. People think that K2 or Salomon invented the twin, but, it was actually a ski called the Banshee. It was all wood, no edges, and has a raised, pointy tail. Im going to guess someone slid a rail or something of the sort back then by accident. No idea. But I do know the first twin tip was made in the 1930's. It was from an old edition of FREEZE.