CHICAGO — At the entrance of “Thinking of You. I Mean Me. I Mean You.” the striking, flag-planting new Barbara Kruger retrospective (and elaboration) at the Art Institute of Chicago, you’re greeted with one of the artist’s videos, installed like a blockade. It’s of an image being assembled like a jigsaw puzzle, clacking loudly with each new added piece. You stand before it, as if staring into a Las Vegas slot machine — a tractor beam of tsk-tsk propaganda. When complete, the message is delivered with a thump: “I shop therefore I am.” That’s familiar Kruger wisdom, deploying the tools of mass communication shepherding to make the sheep think. On the walls on either side of this work are slates of Kruger copycats — derivative works combining text and found material from media — by mostly anonymous designers and agitators. They co-opt Kruger’s famous templates (the colors, fonts, phrasings, and so on) for myriad purposes, and are collaged by the artist with abandon: memes, marketing materials, metacritique. A still of Patrick Bateman overlaid with “Die Yuppie Scum!” A pic of Paris Hilton with the text “100% Natural.” An ad for the 2007 French presidential campaign of Ségolène Royal. Some scattered phrases jump out: “I Am Frivolous.” “Wage Slave.” “You Are Not Yourself.” “iPhone Therefore I Am.” “Forsaken.”