The legs are robust and often clad in bristles, hairs or spines. Synthetic filaments last longer than natural bristles. There may also be protrusions such as microvilli, cilia, bristles, spines and tubercles. Dreams form the bristles of the artist's brush. An electric toothbrush performs rotations of its bristles and cleans hard to reach places. They are tipped with a pappus of slender bristles. The stems have very numerous stiff bristles and many straight prickles. The winter coat consists of long, coarse bristles underlaid with short brown downy fur. The valves are sometimes modified into thick bristles or short teeth. Most fairyflies possess wings with long bristles (marginal setae) on the fringes. Tarantulas have evolved specialized bristles, or setae, to defend themselves against predators. The body is often ornamented with ridges, rings, bristles, or other distinctive structures. A tarantula perceives its surroundings primarily via sensory organs called setae (bristles or spines). The fruit is a cypsela tipped with a pappus of barbed bristles or scales. Its only hair is the ear fringes and tail bristles.