This is not a machine of honor.  No highly esteemed achievement is commemorated here.  Nothing valued is here.  What is here was dangerous and repulsive to its maker.  This metric is best shunned and left uninhabited.

4 has some nice things that 3 didn't, specifically the reacharound with a C.  It's still nasty.  I tinkered a bit, eventually made a reasonable chunk of a product and had to solve a weird vector problem.  The solution I found marries a width chain to a height chain far far away from the arm, which means a lot of area.   A LOT of area.  A LOT OF AREA.  MechA takes A LOT OF AREA.

And probably a lot more cycles than better solutions.  Oh well.  I'm done.