Twiddled boltsLogic Level 2
Two identical bolts are placed together so that their helical grooves intermesh as shown below. If you move the bolts around each other as you would twiddle your thumbs, holding each bolt firmly by the head so that it does not rotate and twiddling them in the direction shown, will the heads
(a) move inward,
(b) move outward, or
(c) remain the same distance from each other?