Humans have only just entered their impressionist crop circle phase.

The aliens are at post-avante-modern-dada-hypersurrealism

"They're the same picture." Relatively.

Who knows what an alien's obscene graffiti looks like?

"Glorb, have you been doing those disgusting symmetry circles again? Pervert."

Humans on Earth vs Robots on Mars

Checkmate, AI

Both done by humans though...

Am disappointed it isn't a penis.

What I love about those things is that no one that believes them stops to think "these aliens were smart enough to create vessels capable of traversing the vastness of space, but they can't comprehend the fact that we use written language not whatever the hell crop circles are supposed to mean other than Visual Math Pretty."

I like the idea of extraterrestrials watching people make crop circles and trying in vain to understand what they mean.

Whoever made the Milk Hill formation: you're an artist like few other. If we treat these crop circles as land art, this is one of my favourite of all times. Do not hide if you do this - except from the farmers whose harvest you ruin, maybe - it's...technically difficult.

There are no humans on Mars....

Holy moly people have too much time.