How to play

There are hidden four groups of four words among these 16. Tap four words you think go together, then press Submit.

Get a group right and it locks in with its color and category. Each group has a different difficulty, from yellow (easiest) to purple (hardest).

There is no mistake limit, so guess as often as you like. A wrong guess will tell you if you were one away (three of your four belong together). Solve all four groups to reveal the cache.