I saw this one day, and decided to write a Processing program to generate this sort of graph for any arbitrary shape. How it works is that a programmer can define their shape using the setLoc and lineTo methods of PeriodicShape. Thus, the programmer can create any shape that is made up of line segments (they don't even need to be connected). The programmer also specifies a center to "scan" around. The program displays both horizontal and vertical graphs, based off both the x- and y-coordinates of the intersections with the shape. The provided code comes with a triangle as an example shape, so the program can be run without modification to show a demo simulation.