From the Super Mario Wiki
Screwtop Platforms are platforms in New Super Mario Bros. U that move in a set direction when spun on. They have a bolt on them which needs to be spun to activate the platform and make it move. The direction that they spin in can be represented by a thin white line which symbolizes its movement path. They slowly spin back in the direction they came from when the player is not on them. Screwtop Platforms are the main gimmicks of Screwtop Tower, in which they must be used to progress and are also only used in this level. These are also found in New Super Luigi U and appear in Sumo Bro's Spinning Tower. They function in the same way as its New Super Mario Bros. U counterpart.