Abstract: A fluid displacement device including a center shaft and a plurality of vanes. Each of the plurality of vanes has an inner edge, an outer edge, and a spiraling edge disposed between the inner edge and the outer edge. The spiraling edge of each of the plurality of vanes follows a Fibonacci spiral based on circular arcs traced through a Fibonacci tiling comprising squares having side lengths that are a multiple of at least five successive Fibonacci numbers.

Abstract: A fluid displacement device including a center shaft and a plurality of vanes. Each of the plurality of vanes has an inner edge, an outer edge, and a spiraling edge disposed between the inner edge and the outer edge. The spiraling edge of each of the plurality of vanes follows a Fibonacci spiral based on circular arcs traced through a Fibonacci tiling comprising squares having side lengths that are a multiple of at least five successive Fibonacci numbers.

Abstract: An ergonomic writing instrument comprising a writing instrument and a shell. The shell has a longitudinal axis and opposite ends and a hollow interior. The writing instrument is positioned within the shell with its operational end extending from one end of the shell. The portion of the shell furthest from the operational end is heel or "D" shaped, thus providing an ergonomically superior shape for a writing instrument. One can pick up this writing instrument and very easily grip the writing instrument correctly. Due to the comfortable conformity of the writing instrument to the natural arch between the thumb and the index finger, one can write for long periods without the fatigue or writing cramps which ordinarily accompany prolonged handwriting with conventionally shaped writing instruments.

Abstract: An anti-slip grab rail and grab rail assembly, the grab rail providing improved gripping surfaces which, in the preferred embodiments, are formed by a plurality of exposed surfaces of a rigid elongate bar alternating with a plurality of elastomeric members extending longitudinally of the bar. The elastomeric members preferably take the form of inserts secured within cavities that extend longitudinally of the bar at the surface of the bar. The inserts may be secured within the cavities by aligning the inserts adjacent to the cavities and pushing them transversely into the cavities such that the inserts snap into place and are retained by an interference fit with a portion of a structure of the rail.