The Quatrefoil has been used in gothic architecture for centuries and has recently had a resurgence in the interiors world. The quatrefoil is by definition a round shape commonly used in windows with four equal lobes, like a four-leafed clover.
You can see many different executions of the Quatrefoil in interiors below, my favorite being the Asilah Bed from Ironies, the big brother company of Oly, which Thom Filicia used in this bedroom.