Prints a grid on the screen of the Commodore PET and CBM computers
It is a BASIC program with a data line machine language extension. This draws a grid on the screen quickly. The rest can be found in the REM line documentation.
The source code of the machine language routine can be found in the "source" directory. The program was written with C64 studio.
The program was tested physically on a CBM3016 and a CBM8032. Further on VICE with all possible (PET) machines, BASIC 1, 2 and 4.
It displays 5 different grids, which can be cycled by pressing any key. Stop the program with RUN/STOP.
The purpose is to recognize any non-linearities and view "the shake".