Kara wants to walk a slalom between the trees. The start of the slalom is show in the picture. Program Kara so that he endlessly walks the slalom back and forth. Initially, Kara is positioned so that he first has to take a left turn.

The length of the course (how many trees the slalom has) is unkown to Kara. Also, he should not care whether the trees are horizontally or vertically aligned.