Magic 8 ball
One outcome in 20
Drawn in your browser · nothing stored
Ask a yes-or-no question and one of twenty answers comes back. Ten are affirmative, five are non-committal and five are negative: the same distribution moulded into the icosahedral die inside the original toy.
How to use the Magic 8 ball
The twenty answers have barely changed since the toy took its familiar shape, and the split across them is deliberate: half affirmative, a quarter negative, and a quarter refusing to commit. The non-committal five are the commercially clever part. "Reply hazy, try again" and "Concentrate and ask again" are not answers; they are instructions to shake the ball a second time, and a toy that asks to be used again is a toy that keeps being used. Every face here is equally likely, drawn from your browser’s cryptographic generator, so an affirmative comes up exactly half the time and asking three times gives you at least one yes with probability seven in eight.
Where the twenty answers came from
The device is older than the eight ball around it. Albert Carter, son of a Cincinnati clairvoyant, filed a patent in 1944 for a "liquid filled dice agitator": a tube of thick dark liquid with a many-sided die floating in it, so that whichever face drifted against the window was the answer. He did not live to see it granted in 1948. Abe Bookman, his partner in the company Alabe Crafts, kept redesigning it, and in 1950 Brunswick Billiards commissioned a version housed in a black-and-white eight ball. The housing was a marketing decision; the mechanism underneath is the 1944 one, and the icosahedron is why there are exactly twenty answers rather than some rounder number.
The ball does not know anything, which is the part worth being clear about. Its only real function is to make you notice a preference you had not stated. If you catch yourself shaking it a second time, the first answer already told you something and it was not about the future.
What people use it for
- Ending a question you have already put to three people
- Running a party round where everyone gets one question
- Answering questions put by a chat or an audience
- Demonstrating a twenty-outcome draw in a probability lesson
- Testing your own reaction to a yes before committing to one
Questions
Twenty, on the faces of an icosahedral die: ten affirmative, five non-committal and five negative.
Yes. Every face has the same chance, so an affirmative comes up exactly half the time.
One in two for a single ask. Across three asks the chance of at least one affirmative is seven in eight, which is why persistence always feels like it works.
Because a toy that tells you to ask again gets shaken again. "Reply hazy" and "Concentrate and ask again" are the reason the original sold as well as it did.
Albert Carter patented the liquid-filled die mechanism in the 1940s; his partner Abe Bookman put it inside an eight ball in 1950 for Brunswick Billiards.
Nothing stops you, and the second answer is independent of the first. That is also the point at which the ball stops being useful and you should trust your own preference.
The draw comes from crypto.getRandomValues, the same generator used for cryptographic keys. There is no pattern and no memory.
The question is never typed anywhere and nothing at all leaves the page.