Four colour theorem

Now that we have created a coloured planar graph lets try to play with it. We know because of the four-colour-theorem, that there is a colouring with only 4 colours possible. Follow the instruction at the bottom of the site.
1) Try to colour the graph without using cyan. - Select the colour and then a point to change its colour. - You must not colour two adjacent vertices in the same colour 2) Check your result