Imagine screwing in a screw. Rotation makes lateral movement. Imagine pushing in a sharp-ended screw into something soft. Lateral movement makes rotation. What

Imagine screwing in a screw. Rotation makes lateral movement. Imagine pushing in a sharp-ended screw into something soft. Lateral movement makes rotation. What I believe is happening here is that one screw is being rotated, generating a lateral force on the other screw, rotating it.