Circular triangle are zero. The arbelos is a special case with three collinear vertices and three semicircular edges. Other circular triangles can have a mixture of convex and concave circular arc edges. Long arcs can produce concave figures regardless of whether individual edges are curved inwards or outwards. Inward curved arcs can create self-intersecting forms, such as the a triquetra figure: Circular triangles can be seen in tessellation. Circular triangle In geometry, a circular triangle is a triangle with circular arc edges. A convex circular triangle may be constructed by three circles intersecting each other and represents the area of intersection. Its
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