 We introduce an algorithm that produces a snapping fixture with such properties in O(n ^5) time , if a snapping fixture exists , and an efficient and robust implementation of this algorithm .
<clarity>  We introduce an algorithm that produces a snapping fixture with such properties in O(n ^5) time , if a snapping fixture exists , and an efficient and robust implementation of this algorithm .
 We introduce an algorithm running in O(n ^5) time , if a snapping fixture exists , and an efficient and robust implementation of this algorithm .