FORTRAN IV programs for plotting mathematical functions. A wire frame is drawn in central projection with “hidden line” removal.
The original program runs on a MODCOMP mainframe build by a company called modular computer systems. This computer was connected to a CalComp drum plotter.
The programs are still working on a i9-9900K CPU running Debian 10. The old FORTRAN IV source code can be compiled with the GNU Fortran compiler. But I don’t have access to the CalComp plotter software. So all NEWPEN and PLOT calls are logged to a file. A Java program later interprets this file to produce Portable Network Graphics.