For inquisitive minds

Hidden Rule.

Experiment. Notice a pattern. Find the rule.

Loading today’s puzzle…

Connecting to the machine…

The evidence

Order matters: left → right

The machine accepts some arrangements and rejects others. One of the six rules explains every result.

Your experiment

0 / 10 tests

Select a position, then change its shape or color.

Editing position 1

What’s the rule?

3 guesses left

Rules that contradict the evidence are crossed out. Select a remaining rule when you’re ready.

A useful experiment separates two ideas. Try changing just one thing.

A small experiment in curiosity.

A machine follows one hidden rule. Your job is to discover it.

  1. Study the evidence. You start with one accepted arrangement and one rejected arrangement.
  2. Build a test. Each of the three positions can be a circle, square, or triangle in blue, gold, or coral. Symbols can repeat.
  3. Compare the result. You have ten experiments. Impossible rules are crossed out for you.
  4. Choose the rule. Exactly one of the six options is correct. You have three guesses.

“Exactly two” means two, not three. “Before” means anywhere to the left, not necessarily next to it. An identical symbol has both the same color and shape.

Today’s puzzle is shared by everyone. Practice links always open the same puzzle. Progress is saved on this device when browser storage is available.

Reveal the rule?

This will finish your puzzle and show the explanation.