[RKDinOKC]

When in 7th Grade (1972) I was put in 9th grade band. The resulting change in my schedule put me the slow Geography class instead of the advanced. Every Friday the "grade challenged" class would watch movies. We specifically tried to pick out editing mistakes. If you look there are lots of things in the b movie westerns like contrails, tire tracks, phone/power lines, etc. We especially liked the ones where you could see the guy that got shot off his horse fall and roll into a dead man's box and toss the dummy out to get trampled.