Comment by int_19h

It was a common rite of passage at the time. I did something very similar, first cloning Borland's TUI, then Win3.1.

The nice thing about Windows of that era - its widgets and their default color scheme was designed to still work with just the original 16 EGA colors (since that was the baseline for video cards back then). To be even more precise, everything other than window title and selection was done in 4 colors - white, black, and two shades of gray. Window/selection added a fifth. Things like selection rectangles and resizable window borders were done using XOR. This all was readily accessible in a DOS app, pretty much regardless of the language.