Logic Masters Deutschland e.V.

The following set of four 5x5 puzzles each utilize a different colouring rule, together with a `vision constraint' which counts coloured cells vertically and horizontally.

Puzzle 1: Snake-Egg.

• Each row and column contains the digits from 1 to 5 exactly once each.
• Snake-egg: shade some cells to draw a single 1-cell-wide path (the 'snake'). The head and tail of the snake are the two cells with circles. The snake cannot branch or touch itself orthogonally, but may touch itself diagonally. The unshaded cells form exactly four orthogonally connected regions (the 'eggs'), one of each size from 1 to 4. An area of size n contains exactly the digits from 1 to n. (The eggs cannot touch orthogonally but may touch diagonally.)
• Cells with squares are on the snake, and the digit in the square indicates how many snake cells are visible from the cell in all vertical and horizontal directions combined, including itself. Non-snake cells obstruct the view.

Puzzle 2: Whisper.

• Each row and column contains the digits from 1 to 5 exactly once each.
• Whisper: shade an orthogonally connected one-cell-wide path of cells which cannot branch or touch itself orthogonally, but may touch itself diagonally. The path starts and ends at the circled cells. Consecutive digits in the path must differ by at least 3.
• Cells with squares are shaded, and the digit in the square indicates how many shaded cells are visible from the cell in all vertical and horizontal directions combined, including itself. Unshaded cells obstruct the view.

Puzzle 3: Tetrominoes.

• Each row and column contains the digits from 1 to 5 exactly once each.
• Tetrominoes: Shade some cells to form four tetrominoes (i.e. four orthogonally connected regions of size four). These tetrominoes may not touch orthogonally, but may touch diagonally. Each tetromino contains the digits 1 to 4 exactly once each.
• Cells with squares are shaded, and the digit in the square indicates how many shaded cells are visible from the cell in all vertical and horizontal directions combined, including itself. Unshaded cells obstruct the view.

Puzzle 4: Aqre.

• Each row and column contains the digits from 1 to 5 exactly once each.
• Aqre: shade an orthogonally connected group of cells so that there are no runs of four or more consecutive shaded or unshaded cells, vertically or horizontally. Unshaded cells form orthogonally connected regions which may touch diagonally, and in which digits do not repeat.
• Cells with a number in the corner are unshaded, and the number is the sum of the digits in the corresponding region of unshaded cells. (All such numbers may not be given.)
• Cells with squares are shaded, and the digit in the square indicates how many shaded cells are visible from the cell in all vertical and horizontal directions combined, including itself. Unshaded cells obstruct the view.