From cave paintings to modern-day graffiti, humanity can’t hold itself back from scrawling on vertical surfaces. Now, though, we can get a robot to do the job for us. Hanging from two wires strung from nails, the disc-shaped Scribit ($349) is like a combination of Roomba, Spider-Man, and Picasso. Feed it custom art or select from millions of examples in the Scribit app, and it gets to work with four colour markers. If you fancy something new, Scribit’s eraser pod heats to 65°C to evaporate existing compositions. Ideal, then, for businesses who fancy updating daily menus or schedules, art lovers who want something new on their wall every night, or nutcases desperate to broadcast tweets by way of their living room window.