I have a Putersen monitor arm capable of holding three 27" monitors. However, that's true only if monitors are in-line and not by angle. For having side monitors turned at an angle, the arm is simply to short (which is really a bummer). Hence I created a mount that offsets monitor to a side. Looks like modern monitors are lightweight enough for the mount and arm (using LG 27UL600).
The author hasn't provided the model origin yet.