This takes a bit of teamwork to solve. Have pc face the 'bridge'. Directions are based upon that facing, given moving around can change angle, and thus right/left directions. Have the other party members step on the stones in accordance to these directions:
Right 1, right 2, left 3 PC steps on first section of bridge right 2, left 3, left 6 PC steps onto second section Right 2, right 4, left 6 Right 4, left 1, left 6 PC moves to third section Right 4, right 5, left 1 Right 5, left 1, left 5 PC crosses bridge.