thereograms

Thereograms are a type of logic puzzle that involves deducing the location of hidden objects within a grid. The puzzle presents a grid, often square, and a set of clues associated with each row and column. These clues typically indicate the number of hidden objects in that particular row or column. The solver's task is to fill in the grid cells, marking where objects are present and where they are absent, based on the provided numerical clues.

The name "thereogram" is a portmanteau of "there is" and "telegram," referencing the way the clues concisely communicate information about the grid's contents, similar to a brief message. The core mechanic involves understanding that the sum of the objects in a row or column must match the given clue. By strategically placing objects and eliminating possibilities, solvers can gradually reveal the complete arrangement.

Thereograms are similar in principle to other grid-based logic puzzles like Sudoku or Nonograms, but they focus specifically on counting the occurrences of a single type of hidden item. They test logical deduction and spatial reasoning skills. While typically presented as a black and white puzzle, variations can exist with multiple types of objects or more complex clue systems. The difficulty of a thereogram can vary based on the size of the grid and the complexity of the deductions required.