This appears to be my first newsgroup posting in 1993, after using Turbo Pascal for 6 years, since 1987.
My subsequent messages weren't there, but these postings indicated I was using TVGraph for another 2 years at least.
I was the sysop of 6:600/608 at that time, a node of Fidonet.
In 2017, with the release of Delphi 10.2 Tokyo, Embarcadero introduced a specialized implementation of the Observer pattern into the System.Classes unit. While it has been in the wild for 9 years, it remains a "hidden" architecture for many, primarily because it serves as the invisible engine behind LiveBindings. Other than live bindings, you can also use the Observer pattern as a way to update component settings to the Windows registry, an .ini file, or persist it elsewhere.
System.Classes