Don’t worry: This stack of giant teacups isn’t about to tumble down. It’s an optical illusion—something that looks different than it really is. Artist Leon Keer painted the four enormous teacups on a building in Helsingborg, Sweden. Although the image looks 3-D, it’s actually a flat mural. 

To bring the painting to life, Keer worked with developers to create a smartphone app. It plays an animation of the cups shattering into pieces.