When Johannes Kestler invented Campixu in 2008, he thought that a colour version would follow soon. But it was not to be that easy. He experimented with some variations, but they didn’t really feel like a natural extension of the single-colour Campixu puzzle.
In December 2017, he decided to make a Campixu app, which would definitely require colourful puzzles. And, as the saying goes, it transpired that necessity was indeed the mother of invention. This time, he came up with an idea that looked impossible at first sight. But he persevered and succeeded.
Interestingly, the rules for the colour versions seem so natural now that he can’t believe it took so long to find them. But, as with so many inventions, afterwards, it always looks easy.
Two numbers are given at the start of each row and column for every colour. The first is the total number of cells of that colour in the line, and the second is the number of groups of that colour. All cells in any inner region, marked with a bold outline, must be of the same colour.
It should be noted that there does not have to be a free cell between two blocks of different colours, and that the order in which the colours appear along a line is not specified.