You can tell when you’ve got an allergy. You can tell when you’re feeling faint. You can tell when you’re down with the flu, but there are some things you can’t tell. For instance, how much UV your skin has been exposed to. L’Oreal plans to change that with its UV Sense, a series of smart, battery-free ornamental stickers that sit anywhere on your body (although I do have to admit they look rather pretty on the nails). These stickers comprise patterns made from photoreactive dyes that change based on how much UV they’re exposed to. In short, the more time you spend outside, the more change the stickers register. They even broadcast the data to your phone, allowing you to monitor how healthy your skin is and whether you need an extra dollop of sunscreen or not. Designed by the minds at Fuseproject, the tiles wonderfully blend aesthetics and medical functionality (seamlessly, if I may add). Perfectly capturing the style of the demographic they’re meant for, L’Oreal hopes that these stick-on UV meters will be as common as carrying chapstick around with you. Designer: Yves Behar (Fuseproject) for L’Oreal