Week 2: Up in the Air

Visual clue. Feathered animals shown in the air or perched: an eagle, an owl, a parrot and a flamingo.

The hook. All four are birds that fly. The flamingo may not look like a strong flyer, but flocks migrate hundreds of miles.

Here's the trap we set. Eight tiles show birds. If you grabbed the first four birds you saw, you probably picked up a penguin or an ostrich. Those cannot fly.

Visual clue. Small creatures with six legs: a butterfly, a bee, a dragonfly and a ladybird.

The hook. All four are insects. Three fly; the ladybird flies too, with wings folded under its spotted shell.

Here's the trap we set. The butterfly and dragonfly have big, obvious wings and tempt a "wings" group with the birds. The puzzle sorts by what the animal is, not by whether it has wings.

Visual clue. Human inventions in the sky: an aeroplane, a helicopter, a hot-air balloon and an airship.

The hook. Balloons (1783), airships (1852), aeroplanes (1903) and helicopters (1930s) are the four great ways people learned to fly.

Here's the trap we set. The zeppelin is long and grey like a whale, and a few players read it as an animal. It is a machine.

Visual clue. Four birds with tiny or useless wings: a penguin, an ostrich, a kiwi and an emu.

The hook. Penguins swim, ostriches and emus run, and the kiwi walks by night. None of them can fly.

Here's the trap we set. This is the group hiding inside the birds. It only appears once the flying birds are gone and you ask what the four leftover birds have in common: nothing about flying, and that is the answer.