In the 'Parasites Lost' episode where Fry eats the truck stop sandwich, Leela falls in love with the new improved Fry. When they walk into Leela's apartment, the walls in the front room are painted white. When they are in the bedroom and Leela says "Oh Fry, I love what you've become.", Fry walks out. but when we look back into the front room and the walls are clearly yellow. Magic!