I had an English teacher at university who had been an actor with a Shakespeare company before WW II. When he was drafted, the Army, in it's infinite wisdom, decided a guy with a master's degree in theatre should be put to use teaching draftees in the finer arts of modern warfare. The first task he had involved teaching how to camouflage various pieces of heavy equipment--trucks, tanks, artillery--in the field.
He had a crew set up examples for the unlearned to view, two-by-two, a la Noah. Each pair of pieces were to give the students an example of the right way and the wrong way to effect the camouflaging. After the classroom work and the field examples, the young men were given a test to be sure the techniques had been learned. You can see this coming, right? About 75% of them cited the wrong way as the correct method.
He decided then and there that he would never again show anyone the wrong way to do something.