One of those strategies is to create a concrete that “self-heals,” and in a new study, scientists used synthetic lichen to patch cracks autonomously (meaning that outside nutrients don’t need to be applied for the repair to take place. Of course, self-healing concrete isn’t new—headlines have popped up for years touting new techniques for making concrete long lasting, and some have even used microbes. In lab tests, the synthetic lichen was able to fill cracks—even in concrete—relying on just sunlight and air for food. Using this autonomous repair system can not only extend the life of concrete, but also cut down on repair costs. Challenges still remain for the widespread adoption of self-healing concrete.