Continuity mistake: Throughout the movie, Alan Arkin is carrying in his breast pocket a Cross Chrome pen to write messages with on his pad. (He is a deaf mute.) But in the scene where he is on the porch with Sondra Locke and he is drawing a picture for her, he pulls that pen out of his pocket, yet when the scene cuts to a different angle showing him actually drawing on his pad, it is a thick, black felt tip pen. (01:25:00)
Continuity mistake: The ford transit van used by the demolition men Ron and Mr Perry changes between scenes from a long wheelbase van reg no. KGX107D to a standard van reg no. OYO576F.
Continuity mistake: The girl named Why is in the bathtub. Frédérique brought her a cup of tea that she indignantly put aside because it had an excess 1/2 sugarcube. She put the cup to the edge of the tub with the spoon facing one direction, but during the conversation the spoon turns 180° on its own during a cut. (00:07:40)