# GridColouring

This construal demonstrates a puzzle - each hexagon must be coloured, with no adjacent hexagons having the same colour, in such a way that four hexagons are red, four hexagons yellow, four hexagons blue and three green.

Coloured buttons are shown on each hexagon, the construal is designed to help the user with solving the puzzle by only showing buttons that lead to a valid move.

This construal illustrates colouring of planar maps and the Four Colour Theorem.

The latest version of the construal, based on key ideas from Jonny's original prototype but not yet completed, has been developed by WMB. The restriction on the number of times each colour is used has not yet been implemented for instance.

This is a construal that has potential both for exercises related to solving the puzzle, mathematics, and the nature of making construals.

- solving the puzzle, e.g.

can try solving with or without the computer support

can consider different restrictions placed on number of uses of colours

e.g. find a 3-colouring and express using a systematic definition

- mathematics

map colouring problems

regular hexagons

sin and cos for pi/3 - elementary trig - coordinate systems

- the nature of making construals

dependencies governing the hexagons can be monitored whilst colouring

there is good scope for tractable 'bug' fixes

- e.g. missing hexagons in an adjacency list

- the wrong ordering of points in a hexagon