This program was written in 1990 in Turbo Pascal for DOS machines. The functions are discussed in DOI:10.1016/0165-0270(92)90051-E, DOI:10.1016/S0169-2607(96)01781-6 and DOI:10.1016/0165-0270(92)90138-4. It was further developed over decades and can be now compiled with Free Pascal.
The main branch is based on version 9.19 using the wingraph unit from Free Pascal 2.4 which is discontinued. The stable branch ist based on the version 9.04 using the standard graphic window. All other developments have been merged into the stable branch with version 10.01.