arrangements: computes a greedy pseudotriangulation of points, allowing to flip minimal bitangents. (point|segment|polygon|circle)_input: input a scene of disks and constraints. Takes as argument a file name to store the disks, and an optional file name to store the constraints. First input the disks (to complete a polygon, click on the right button), then press enter, then input the constraints (click the source then the target disk, a left click will yield a left bitangent, and a right click a right bitangent), then press enter to complete. The backspace key allows to pop the previously input disks or constraints. (point|segment|polygon|circle)_display: displays a scene of disks and constraints (point|segment|polygon|circle)_compute_vc: computes the visibility complex of a scene, and displays the bitangents. (point|segment|polygon|circle)_compute_vc: computes and displays the free bitangents of a scene. (point|segment|polygon)_compute_sp: computes and displays the shortest path connecting the first two disks of a scene. The directory ../../examples/Visibility_complex/data contains example scenes. The .d files contain the disks, the .c contain the constraints. The *compute_(vc|bit|sp) and *display demos take as first argument the file containing the disks, and, optionally, as second argument the file containing the constraints.