Abstract: A blind type covering most appropriate to a semi-circular window, constructed of a multible slats, strung together in such a way as to cover a 180.degree. arch when closed, in an even and symmetrical manner. One or two sets of these blades pivot either manually or mechanically from a rigid base attached to or near the window frame. The blades may be composed of virtually any material capable of being self supporting at the lengths necessary, and may also be hollow in nature, allowing for a covering material. By incorporating slots in the blades and a track system, the blades may be pulled out to fully compensate for the irregularities of the arch itself. Further, a quick coupling system may be used to attach the blind to the window, for ease of maintenance.