you can plot perfect circles at any size. all you need is rope and a weight or stake to hold the center point.
some guys used this to put the micron logo on top of a factory, much larger than any circles you see plotted in these crops. still doesn't explain how they would have done this with crops though.
with modern technology, and by modern I mean 1980's.... someone can use GPS and a robotic lawnmower to effectively create a computer controlled crop plotter, using the same mathematics and vectors used by large-format vinyl cutters, commercial routers or CNC, laser engravers, waterjet cut, etc.
anyways, my point is, compters can easily control a pen, knife, router, laser, blade, or jet of water to create perfect shapes and immensely complex patterns, I see it every day at work. I am pretty sure whoever did this was using a digital aid of some sort, and able to move and create negative space without disturbing positive space.... meaning they were flying. at night. using computers to plot perfect shapes. without being seen or heard by anyone, with nobody having video of anything, except fools filming themselves making FAIL circles like someone said.
I also saw a documentary showing some crop circles that had been marked by irradiation, and all the stalks were bent at perfect angles in ways that would be impossible for humans to accomplish overnight, without there being hundreds of them to be witnessed. also the radiation... 100+ humans doing some overnight shit without being seen and while being irradiated = WTF R U SERIOUS, BRO?
all that shit aside, I work in the signage industry, and like I said people have plotted very large logos and designs visible from space and such, the only thing is they couldn't do it overnight using any technique known to man. no technology or method, manpower, nothing available is able to plot something like the pic below overnight. nothing. and if there is, they are fucking retards for not selling their shit off for billions of dollars to the sign industry.
seriously, whoever these guys are, who can plot these perfect designs at such scale within a one night period without ever being seen, they have a GIANT market available to them. not only for the technology/method but simply because they are able to do it with such a presumably small group and so fast, they can probably undercut all competition by 90%