Every word is in one row and one column. Pick four that make a group.
Sixteen words fit a 4×4 grid. Each row is a group and each column is a group, so every word belongs to one of each.
Pick four words that make a group and submit. Found rows are edged in blue, columns in orange, and a word with both locks in place.
Watch for red herrings: some words look like they fit two groups. You can make four mistakes.
New puzzles every day at 7:00. Free, no account. Part of Five Ahas, five daily puzzles.