Pretty cool. Mars doesnt have jet streams containing the bad weather during the permanently dark winter on the poles, so the polar caps can grow down to like (+/-)50 degrees latitude during their respective hemisphere's winter. Imagine earth down to Canada and northern Europe encased in dry ice. Must be crazy surface activity when its all melting or sublimating (tips fedora). Back before digital imaging, people used to stare are those through telescopes and imagine that they saw greenish / plant hues when the polar caps would recede in the spring, along with canals and stuff. I can see weird features caused by dry ice interacting with the rocks and dirt, like water ice blowing up around mount st helens and creating strange patterns.