Galaxies and Tetrominoes by Palmer Mebane

Galaxies by Palmer Mebane

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or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a shading mode.)

Theme: Logical

Author/Opus: This is the 43rd puzzle from our contributing puzzlemaster Palmer Mebane.

Rules: Combination of Tetromino/object placement and Spiral Galaxies puzzle styles. Place the seven tetromino shapes into the grid, rotations allowed but not reflections. Tetrominoes do not touch each other not even diagonally and they do not cover any cell with part of a white circle. Digits on the left/top of the grid indicate the number of cells used by tetrominoes in that row/column. Digits on the right/bottom indicate the number of different tetromino shapes partially in that row/column. All remaining white cells must be part of connected regions – “galaxies” – with rotational symmetry. Each galaxy must have exactly one circle at its center of rotational symmetry.

Answer String: For each cell in the marked rows, enter the tetromino shape (as a capital letter IJLOSTZ) or the galaxy size in cells (enter just the last digit for any two-digit number). Separate the rows with a comma. An example answer would be “772TTT44SS,6664333LLL”.

Time Standards (highlight to view): Grandmaster = 4:45, Master = 9:30, Expert = 19:00

Solution: PDF; a solution video is also available here.

Note: Follow this link for classic Spiral Galaxies puzzles on this website and this link for variations on Spiral Galaxies puzzles. If you are new to this puzzle type, here are our easiest Spiral Galaxies Puzzles to get started on. More Spiral Galaxies puzzles can be found in The Art of Puzzles 2.

Negative Tetromino by Serkan Yürekli

Negative Tetromino by Serkan Yürekli

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or solve online (using our beta test of Penpa-Edit tools in a composite mode for line/edge drawing)

Theme: Words

Author/Opus: This is the 36th puzzle from our contributing puzzlemaster Serkan Yürekli.

Rules: Divide the white cells into tetrominoes so that no two regions sharing an edge are the same tetromino (L, I, O, S, or T considering rotation and reflection). Regions may contain at most 1 cell with given letters; regions with such a cell CANNOT have the same tetromino shape as any of the letters in that cell. Also, see this example:

Negative Tetromino by Serkan Yürekli

Answer String: Enter the letter of the tetromino region for each cell in the two marked rows from left to right, separating the rows with a comma. Use CAPITAL LETTERS for L, I, O, S, and T.

Time Standards (highlight to view): Grandmaster = 1:15, Master = 2:30, Expert = 5:00

Solution: PDF