The Doppit Almanac · No. 29

Packit, a daily block-packing puzzle

Fit every block so the board fills

What it is

Packit is a packing puzzle. The board is a small grid with a few fixed studs already set in it, and your tray holds a handful of oddly shaped blocks: bars, squares, and the bent L, T, S and Z pieces. Fit every block onto the board so the open squares are all covered, once each, with nothing overlapping and nothing hanging off the edge.

You turn a block to make it fit, but you never flip it over, so an L and its mirror are two different pieces. The studs never move, so you pack around them. Every board has exactly one way the blocks all fit, and the tight corners the studs leave usually decide where the first piece has to go.

How it plays

• Cover every open square exactly once. No overlaps, and no block hanging off the edge.
• Tap a block to turn it a quarter turn. Blocks turn but never flip.
• The dark studs are fixed. Pack the blocks around them, never over them.
• Drag a block onto the board, or take it in hand and tap an open square. Tap a placed block to lift it back out.
• Stuck? Hint seats a block that has a forced home, or lifts one that cannot belong.

The difficulties

Three frames, three grains. Easy is a five-by-five that packs in thirty seconds to a minute, cut so there is a forced opening and you rarely stall. Medium is a six-by-six of one to three minutes, with room to try a piece two ways. Hard is a seven-by-seven of three to six minutes, more pieces and less to grip, so more of it is honest trial. Expert is that same seven-by-seven cut below what hard permits: on the boards measured, one block in ten to one in five has a single place to go, and you carry the rest. A fresh board is dealt every day, for nothing. Expert sits outside the daily rota, for practice.

Nearby in the almanac: Dominit, Nonit and Campit