Left mouse button on a point determines the next center,
drag the mouse, and mouse up determines the radius. If you're not sure, hit the "Pick a point for me" button. Red - boundary of the union of the circular disks Yellow - Circular disks that lie on the boundary of the union. At least
one vertex of the polygon is outside the circle. Blue - Circular disks that are interior to the union. The polygon is entirely inside the disk. Black - Polygons associated with the circular disks - restricting the disks to their polygons gives a collection of
disjoint sets which cover the union. A restricted Laguerre-Voronoi diagram. If two circles overlap there is (usually) an edge in the diagram through the
points at which the circles intersect. Thin Black - The dual of the polygons - a restricted Delaunay triangulation. If two circles overlap there is a green edge
between their centers.
Points in the polygon that are on the circle bounding it's disk are on the boundary of the union.