Comment by spogbiper

interesting. gemini 2.5 pro considered that it might be "AutoCAD" but decided it was not:

"A specific user recollection of playing "Connect Four" within a version of AutoCAD for DOS was investigated. While this suggests the possibility of such a game existing within that specific computer-aided design (CAD) program, no widespread documentation or confirmation of this feature as a standard component of AutoCAD could be found. It is plausible that this was a result of a third-party add-on, a custom AutoLISP routine (a scripting language used in AutoCAD), or a misremembered detail."