I've been seeing these little figures in crosswalks around downtown Chicago for a few months. At first I thought that there was just one - not having paid close attention to which crosswalk I was in when I noticed it. Then I realized that there were multiple ones in different colors. There was even a three dimensional one (the bottom photo) on the light pole by the Art Institute.
I asked around. A friend said he suspected they were outer space aliens who, sadly, didn't understand how to cross streets in Chicago. I saw a woman take a picture of one so immediately asked her if she knew what they were (she didn't).
With some help, I finally stumbled on the right combination of search words in Google to get a reasonable explanation. It's stikman! stikman is a New York based street artist who leaves this signature figure as a calling card. A Washington Post reporter interviewed stikman after noticing his work all over Washington, DC.