as a coating. It is also used in some applications where stable, vibrant color is required. It is flexible enough that it can be designed to have a pattern. Mimicking fireflies to improve LED efficiency When observing fireflies (Photuris sp.) using SEM, it was observed that their light emitting cuticle had a specific 2D periodic structure. It is structured following a “factory roof” like pattern with scales oriented at a tilted slope and a sharp edge on the protruding side of the scales. When modeling a similar structure using a photoresist layer on light emitting diodes (LEDs), it resulted in a 68% power increase and 55% increase in light extraction efficiency (LEE). This technology reduces the amount of energy consumed to produce the same amount of light. Responsive materials Responsive materials are materials or devices that can respond to external stimuli as they occur. A little bit of time is taken to adjust to the new surroundings, but the idea remains consistent with what is seen in nature. The most commonly used examples are the chameleon or octopus, as their responsive skin allows them to change the color or even the texture of their skin. The mechanisms behind these tactics are called chromatophores, which are pigment-filled sacs that uses muscles and nerves to change the animal's external appearance. These chromatophores are activated by neuronal activity, so an animal can change its color just by thinking about it. The animal uses another mechanism to be able to know what color or shape to take; a photo-sensitive cell within their skin called opsin is able to detect light (and possibly color). The animal can use these opsins to their advantage to quickly assess their surroundings, before turning on their chromatophores to accurately camouflage to their circumstances. A lot of creatures have camouflage incorporated into their bodies — take the fish in the figure on the right for example. In this hypothetical, the animal can appear in two different ways depending on their surroundings: in the middle of the ocean away from all solid objects, it can appear near-translucent; near the sea floor where potential predators will only sense it from above, it can turn darker to naturally blend in with the rocky bottom. Many fish, such as the marine hatchetfish, use a combination of camouflage techniques to achieve these appearances. Silvering, a common tactic, utilizes highly reflective scales to reflect the surrounding