Left here without comment ....
BECMI for the Grognards under the sky
ADnD for the Neck beards in their halls of stone
3.X for the geeks and gamers doomed to die
OneDnD for the Williams on her dark throne,
In the land of Hasbro where the Lawyers lie.
OneDnD to rule them all,
OneDnD to find them,
OneDnD to bring them all,
and in the darkness bind them,
In the Land of Hasbro where the Lawyers lie.
BECMI stands for Basic/Expert/Companion/Master/Immortal. Each was a box set of game system that developed in parallel to early Advanced D&D,