“What does Damien Hirst have to do with McDonald’s? Nothing.” So begins a perplexing Instagram video introducing an installation organized by Nicolas Ballario, founder of a Milan-based communications agency, that was on view as part of Milan Design Week. The immersive installation, “POOL. Ti sblocco un ricordo” (“Pool: I’ll Unlock a Memory for You”), is part of a series of offsite exhibitions collectively called Tortona Rocks, in the Tortona neighborhood of Milan. The centerpiece of “POOL” is a large swimming pool-shaped pit full of hundreds of thousands of colorful balls, like a McDonald’s PlayPlace ball pit on steroids. So, what does the provocative British artist have to do with all of this? Ballario’s video is unclear, explaining that Hirst’s relevance to the project, which is intended to celebrate McDonald’s 40th anniversary in Italy, is, in fact, irrelevant. “Art is compelling when it is ambiguous, when it is disorienting and fills you with doubt,” he says. Okay, then! Acco...