Hidoku and Numbrix

Hidoku is the untrademarked name of Hidato™, a puzzle with the objective of creating a continuous path of numbers from lowest to highest, filling the given grid completely. The numbers can be adjacent left/right, up/down or diagonally. Each grid includes the lowest and highest numbers and other givens that ensure a unique solution. The difficulty of the puzzle is increased by having fewer givens to start from.

Numbrix is a slightly simplified variation of Hidato™. In Numbrix the numbers cannot be adjacent diagonally, only up/down and left/right. The objective remains the same, to create a continuous path from lowest to highest number, filling the grid completely.

Due to the constraint of not allowing diagonal paths, Numbrix is usually only played on a square or rectangular grid. Whereas with Hidoku it's possible to create grids of virtually any shape, with some limitations, making more interesting and appealing possibilities.