Abstract: A sensory device may include a bottom surface, a perimeter wall extending upward from the bottom surface to a perimeter height and a plurality of projections extending upward from the bottom surface to a projection height. The plurality of projections may include a first set, a second set, and a third set, where projections within a given set have a similar structure to each other but a distinct structure relative to projections in other sets. Projections may be (a) generally cylindrical in shape, (b) disposed in a linear manner, (c) disposed as a plurality of concentric circular segments, or (d) disposed as a plurality of coupled linear segments.

Abstract: A sensory device may include a bottom surface, a perimeter wall extending upward from the bottom surface to a perimeter height and a plurality of projections extending upward from the bottom surface to a projection height. The plurality of projections may include a first set, a second set, and a third set, where projections within a given set have a similar structure to each other but a distinct structure relative to projections in other sets. Projections may be (a) generally cylindrical in shape, (b) disposed in a linear manner, (c) disposed as a plurality of concentric circular segments, or (d) disposed as a plurality of coupled linear segments.