Goal: sort the 16 tiles into four hidden groups of four related anatomy words.

How: tap four tiles you think belong together, then press Submit. Guess a group right and it locks in with its category name.

Each wrong group of four costs one of your four mistakes — use them all up and the game ends and shows the answers.

Watch for traps: some words look like they fit two groups, but only one arrangement is correct. One new puzzle a day.