Nail clipper allows for removal of any excess nail that is jagged or has been missed. Nail clippers occasionally come with a pocket knife or a nail catcher; the multi-purpose nail clipper was invented by Hungarian inventor David Gestetner. The nail clipper consists of a head which may be concave or convex. Specialized nail clippers which have convex clipping ends are intended for trimming toenails, while concave clipping ends are for fingernails. The cutting head may be manufactured to be parallel or perpendicular to the principal axis of the cutter. Cutting heads which are parallel to the principal axis are made to
Focal cloud Focal cloud A focal cloud is the collection of focal points of an "imperfect" lens or parabolic reflector whether optical, electrostatic or electromagnetic. This includes parabolic antennas and lens-type reflective antennas of all kinds. The effect is analogous to the circle of confusion in photography. In a perfect lens or parabolic reflector, rays parallel to the device's axis striking the lens or reflector all pass through a single point, the focal point. In an imperfectly constructed lens or reflector, rays passing through different parts of the element do not converge to a single point but have different focal points. The