The Italian Institute of Technology says 4.5 trillion cigarette butts are littered each year. Their proposed solution is VERO, for Vacuum-cleaned-Equipped Robot; it's an autonomous robot dog with vacuums attached to its legs.

As for why this form factor was chosen, the Institute says it's ideal for removing cigarette butts from "beaches, small alleys and parks…terrains that are hard to reach for wheeled and tracked robots." Indeed, in the demo video you can see it neatly suck up butts from rocky beaches:

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I do question why they bothered with rear-leg vacuums; after all the cameras are up-front on the "head," and it seems it should be able to handle everything with its two front vac-paws.

Perhaps things have changed, but years ago while visiting France, I was shocked by the amount of dog poop commonly left on sidewalks. (I was living in NYC at the time, where most dog owners will responsibly pick up their dog's droppings.) If that's still the norm in France, perhaps they could develop a VERO that can vacuum dog poop.