Its called 'reading the rock'.
40 years ago I watched a muscle bound man beat the crap out of a rock with a sledgehammer for 3 hours.
Another old guy came along with the same hammer; and within 20 minutes the rock was gone. His words were read the rock boy. they all have fault lines, its knowing where and how to hit or rip. :beatsme
As for those horrible wedge blades; thank Christ I have never had the misfortune to meet them; I,d rather stick to the turnbuckles thanks. just turn the heel down and plough.
The towed rippers in your pic Scrub, were called 'Ben Hurr' rippers over here; like the roman chariots.