SQUARE SHORT LONG ROUND D SHAPE ROUND SLIM SMILEY MULTI SOFT CLOSE TOILET SEAT | eBay
O Shape Soft Close Toilet Seat White with Quick Release for Easy Clean, Top Fixing, Stay Tight Toilet Lid Oval Shape, Heavy Duty UF - China Resin Toilet Seat Cover, PP Toilet
physical - What shape should toilet seats be? - User Experience Stack Exchange