It’s no secret that LED lights have almost infinite applications—one look at Eternity LED Glow’s array of products can tell you that much. But one emerging use of LED lights is the irreverent movement of “throwies,” a kind of guerilla tech street art, and it’s caught our attention at Eternity because we love all things LED… even though we don’t sell them, we think this trend is worth talking about!

You can buy batches of these “throwies” premade online, but it’s cheaper to just make them yourself, not to mention more in the DIY spirit. You create a throwie by taking the two pins of an LED light and connecting them to either side of a lithium battery, placing a small magnet next to the battery, and then taping it all together with electrical tape. It’s easy to find little round magnets in the same shape as the batteries, but be careful not to get magnets that are too small—they need to be able to support the weight of the light. If you choose to secure these parts with a small dab of epoxy, be sure you don’t get any glue between the arms of the LED and the surface of the battery or the connection won’t work. After shopping around and ordering the LEDs, batteries, and magnets, the throwies ring in at less than $1 apiece, which sounds inexpensive until you think about how many singleton LED lights you need to actually make a visual impression.

They’re called “throwies” because of the method of installation—the idea is that you can throw them at metal infrastructure like bridges, signs, or scaffolding, the magnets make them cling where they hit, and everyone will be able to see them but no one will be able to get them down. Usually, no one will even be able to figure out what they are, they’ll just see strange lights twinkling above them and wonder.

There are works of LED public art that are figurative or spell out words, but those pieces are more meditated and it makes more fiscal sense to link multiple LEDs to fewer batteries when you’re able to actually plan a design. Throwies are meant to be used spontaneously, perhaps tossed at random on a night walk with friends through the city. When you have a handful lit up and ready in your bag, it’s like scattering a chest of cartoon jewels.

The lifespan of a throwie’s battery is about two weeks, making it an ephemeral addition to any cityscape. This could be considered an advantage… if the lights were constantly lit, law enforcement might consider it a form of vandalism, but as it is now the throwie just becomes a burnt out bulb stuck to a steel beam that no one will ever be in a position to notice, and what was for a while a point of intrigue and novelty in the darkness becomes invisible both during the day and at night.