Yep, the main abrahamic lineage of X11 window managers. uwm begat twm which begat fvwm which begat bowman...
For quite a while, the window manager space was really dominated by rewrites and adaptions. Not quite sure what the first window managers of GNOME and the K(ool)DE were based on, but I wouldn't be surprised if some familiar names turned up...
An important second clan would be the 9wm ancestry. lwm, aewm and probably a lot of the tiling wm namespace.
Jeepers, I remember being excited when Xaw3D came out. This thread is really making me feel old, and goshdarnit, Pentium Pros with Slackware didn't happen that long ago..
