In a network topology design apparatus for designing a network topology connecting a plurality of points by communication lines so that a predetermined traffic volume is transmitted between the plurality of points, chromosomes wherein the network topology is represented in a matrix are created, and a genetic algorithm is applied to evolve the chromosomes in order to improve cost performance. A control pad or area can be provided to camera users via an application or applet that can be calibrated to provide fluid camera control. The flexible tabs are for stopping the rise of the bundle of coils so as to impede their knotting and to help guiding the wire, as it is pulled to the outside of the drum and unwound from the bundle. The light-permeable panel has a light incident surface and an opposite light emitting surface.