Four Colour Theorem

Show that no more than four colours are required to colour the regions of the map or pattern so that no two adjacent regions have the same colour

Squiggle Rectangles Polygons United States


Click on the regions to fill them with paint. The challenge is to ensure that two regions sharing a border are not filled with the same colour.

Click the 'Check' button when you think you have finished colouring in all of the regions. You can earn a Transum Trophy for getting the colouring correct.

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Friday, November 13, 2015

"The Four Colour Theorem states that it will take no more than four different colours to colour a map or similar diagram so that no two regions sharing a border are coloured in the same colour. The first statement of the Four Colour Theorem appeared in 1852 but surprisingly it wasn’t until 1976 that it was proved with the aid of a computer. A simpler computer-aided proof was published in 1997 and in 2005, the theorem was proven by mathematician Georges Gonthier with general purpose theorem proving software."

The Guardian, Newspaper

Monday, May 7, 2018

"Aubrey de Grey has taken the academic world by surprise after announcing a new solution to the so-called Hadwiger-Nelson problem. You can read about it on The Guardian website."

Conyers Maths, Twitter

Sunday, June 16, 2019

Barbara, England

Thursday, February 11, 2021

"I think that this is interesting to do but still isn't crazily tricky or annoying. the way that it can be done in different pictures makes it even better."

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