8 years ago, I worked on the Vehicle Entry Permit System (VEPS) as the lead engineer. After the project was completed, I left the project.
Today, a friend asked if I was interested in working on a project for a company involved in a project, and when I asked for details of the project, I was told scant details, and I wondered if it was the VEPS project, and it was!
I don't know if I'm interested in returning to a project I worked on many years ago.
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