Isn't it amazing how good design stands the test of time?  If you give that rounded, triangular hand maul to just about any human on the planet, chances are they could figure out how to use it pretty quickly.  It looks like it would fit the hand perfectly and comfortably.  

I know I sound like a wet blanket or something but your old maul has mushroomed and if you use it sooner or later a small piece of the jagged edge will fly off and may hit the user.  I was in construction for 40 years and I know what I’m talking about, it’ll put your eye out, no really it will.  Tools like that, if you want to use it need to be dressed by a black smith or just admired.  When we had pavement breaker bits that looked like that we paid a guy to grind the mushroom off.  Then they were good as new.  I had a guy get a piece of steel from his hammer into an artery in his forearm and he almost bled out. It flew off the head when he was pounding wood stakes.   Just looking out for you, love Al