Which mafia runs a racket on the cement trucks of society?

(Last time I was viewing an x-ray, the orthopedic doctor was surprised to find out that not only does the fracture pattern qualitatively indicate what happened, but there's even a quantitative method to calculate the stresses from angles:

https://en.wikipedia.org/wiki/Mohr%27s_circle

There's even a graphical analogue method, which may be carried out with paper, pen, and protractor, but I've been using software for so long I no longer recall the details.)

Bonus clip: https://www.youtube.com/watch?v=2xlYCvu9pkc