A Sudoku that appears to exist in three dimensions. The creator of the puzzle, Eyal Amitzur, explains:
"In architecture there is a type of view called axonometric projection, where the object is viewed from all three sides (front, side and top) at the same time without the distortion of perspective."
This projection is what makes a Tredoku puzzle appear three-dimensional. The rules are the same as Sudoku, but the puzzle can appear very different. The look of the puzzle is important to Amitzur and he makes a connection between his puzzle and the work of artists M C Escher and Bridget Riley.
The puzzle appeared in 'The Times' for the first time on Boxing Day 2008.
The numbers 1-9 should appear once only in each 3x3 box and 9-square line, but unlike flat Sudoku, the boxes are arranged in three-dimensional space. This means that the 9-square lines could be either straight or bent; follow each line’s direction in search of clues to solve the puzzle.