The Doppit Almanac · No. 07

Fourit, a daily LITS

Shade an L, I, T or S in each region

What it is

Fourit is LITS, the region-shading tetromino puzzle. The grid breaks into outlined regions, and each region takes four shaded cells that form one of four shapes: an L, an I, a T or an S. Rotations and mirrors are the same shape, so a J is an L and a Z is an S. The square is barred.

The four shapes are only half the game. Three rules bind the whole board at once: every shaded cell joins one connected mass, no two-by-two block is ever fully filled, and two shapes of the same kind may not touch across a border. Most of the work is watching those rules conspire.

How it plays

• Shade exactly four cells in each region, forming an L, I, T or S. Turned or mirrored counts the same, and the square is out.
• Every shaded cell joins one connected group, and no two-by-two is ever fully shaded.
• Two shapes of the same kind may not share an edge across a region border.
• There is always a forced next shade, and Hint shows it and says why. No guessing is needed.

The difficulties

Three grids, three grains, plus an expert grain to practise on. Easy is a six-by-six that brushes off in thirty seconds to a minute. Medium is an eight-by-eight of one to three minutes. Hard is a nine-by-nine of three to six minutes, where the twins rule and the two-by-two hide the last shape until late. Expert comes off that same nine-by-nine, and it takes eighteen of those deeper steps to qualify against hard's six, with the usual expert board wanting twenty-six. A fresh board is cut every day, for nothing.

Nearby in the almanac: Sandit, Springit and Stellit