04 Dec 18
@paul-leggett saidYarosh's problem is the most famous version of the task. Hoffmann's was news to me.
I was going to send this link directly to BiggDoggProblem ( he is our resident problem maestro ), but then I thought others would enjoy it.
Here is the link: https://en.chessbase.com/post/the-perfect-babson
I'm more of a solver than composer. Fixing a task like this to be completely dual-free in all full-length variations is certainly beyond my ability!