Engineers have designed a flat metallic surface that allows ice to zip across it without a push to get it going. It takes a few moments, but the results are clear: their novel surface allows a small ice disk to begin moving without any external instigator. “This directional flow of meltwater carried the ice disk along with it,” study co-author Jack Tapocik explained in a statement. While they assumed the ice disk would simply move faster from the very beginning, the result was more complicated. “The fun trick here is that as the meltwater flows beyond the front edge of the ice disk, it creates a puddle,” said Boreyko.