Wheel B is made by drawing wheel A on top of a copy of itself that has been turned. Make wheel C in the same way. Which wheel do you get?

The spokes of A point up and up-right. B keeps them and adds the same pair turned a quarter turn clockwise: right and down-right. C has spokes pointing up, up-left and lower right; a copy turned a quarter turn clockwise adds spokes pointing upper right, right and lower left, so the answer has six spokes: (d). (a) adds a half-turned copy, (b) adds an anticlockwise copy and (c) shows only the turned copy.