GPS is not accurate to a few inches, although making crop circles does not have to be all that complicated.
How Stuff Works
How did the Nazca artists create their giant works of art?
(Although some archaeologists reject the theory as ad hoc, Jim Woodman conducted "experimental archaeology" to determine if the Nazca art was meant to be viewed by balloon. The Nazcas had textiles suitable for balloons, "burn pits" for hot air were found near many of the lines, and the art on Nazca pottery shows what appear to be balloons and kites. The incas, who followed long after the Nazcas, have legends of a boy named Antarqui who flew above the battlefield to report enemy positions.)
How did the ancient Egyptians plot farm land? How did the ancient Greeks plot and build the Parthenon, a structure requiring massive machines and complex stone cutting equipment for its modern renovation? The ancients were very clever at working out these things when there were no other alternatives, and there are lots of clever people today who enjoy doing complex things in "simple" ways that puzzle other people into wondering, "How did they do that?" That was my point in the exclusion principle above: just because one may not be able to puzzle out an alternative does not mean that alternatives do not exist.
I read about a final exam given at an engineering school. The test was administered in a common "science" classroom with sinks, bunsen burners, and other hardware. A 2.5 meter tall lucite tube was bolted to the floor, and a ping pong ball was dropped into it. The exam was to remove the ball from the tube by the end of the exam period using only items available in the room. Students worked in groups. Many groups did things the "hard way" by tearing up T-shirts into strips and fishing the ball out of the tube with some chewing gum, or similarly Rube Goldbergish designs. Some of the brighter groups simply used beakers to fill the tube with water from the sink. None of the groups resorted to UFOs with anti-gravity tractor beams.
Sometimes one can be hobbled by "knowing too much."
An experiment similar to that with the ping pong ball was conducted with chimpanzees in a "natural" enclosure featuring bushes, trees, and a small beach. Feed grain was thrown onto the sand. Many of the younger and more stubborn chimps proceeded to pick the grain out of the sand one grain at a time. A grizzled oldster grabbed a handful of beach and threw it into the water, then scooped the floating grains off the surface of the water.
Many solutions are simple, if we allow ourselves to see them.
"Shoot the hostage." —from the movie
Speed
