The main program leads Kara to the tree, calling the method invertLeaf
before each step. This method tests whether Kara is on a leaf; if yes, Kara picks it up, if no, Kara puts one down.
void invertLeaf() { if (kara.onLeaf()) { kara.removeLeaf(); } else { kara.putLeaf(); } } public void myProgram() { invertLeaf(); while (!kara.treeFront()) { kara.move(); invertLeaf(); } }