Blooper

While at the bank, Erasmus is having a conversation with his mother. A lady extra, wearing a bright lime green suit, is seen passing in the background as the camera is on Bill Mumy. The lady reaches the bank counter. But when the camera cuts to his mother, the extra in green is seen just arriving behind the mother and passing behind her again, on her way to the counter.

Approximately 1:13 into the movie the professor asks Terry, the naked model to cover up and she quickly fastens her bikini top by tying the straps together at the back of her neck. In the next scene you can see her back and the straps are fastened with clips straight down to the horizontal strap.

When asking Erasmus and the computer to divide 17,590,038,552,578 by 680, Erasmus says it can't be done evenly. He says that it can ONLY be divided by 8,191 and 2,147,483,647. When these two numbers are multiplied together, their product is 17,590,038,552,577. They fail to mention it is divisible by 2.

When the Captain launches his carved wooden boat it sinks. If made of wood, it may have capsized but would not have sunk.

When Erasmus is sitting in the car and his father comes out of the unemployment office and they have a conversation in the front seat of the car, it's obvious there is no windshield in the car.

The prior claim that the presence of the "Issaquah" ferry means that the locations are in Washington state and not Sausalito is mistaken. The "Issaquah" was built and operated in Washington state waters 1914-1917 and operated in California 1918-1948. In the 1950s it was divided into apartments and rented. The pilot houses today stand at the entrance to Galilee Harbor in Sausalito and are used as a kind of mini-museum documenting the local history.