Colour Slide is a puzzle in which you have to separate the two sets of coloured counters, so that no two counters overlap. The red counters slide row by row, and the yellow ones slide column by column. Where two counters overlap, you see an orange counter, and when the puzzle is solved there will be no overlaps. Just drag any counter to move it and the counters of the same colour in its row and column. Seems like it ought to be easy, but it's harder than it looks! The usual options to undo and solve are available. You might want to start by tapping the white flag (solve button) to see how it works. The options screen allows you to change the puzzle difficulty, and you can also change the colours if the defaults are hard to see.