We consider a row of six alternating checkers so that a white stone is always followed by a black one. To the right of this arrangement there is sufficient empty space for four checkers. This gives us a total of ten possible positions for the checkers. At any turn, two consecutive checkers can be moved — at the same time and without changing their order — to two consecutive empty spaces. The goal is that all black checkers and all white checkers respectively are grouped together rather than alternating. All six checkers shall still form an uninterrupted row, potentially occupying previously empty spaces but not leaving empty spaces between checkers in the end. Find a solution in three moves!