Of course I had to get sidetracked.
Trying to make a gas lantern, and decided to make something to create a path defined by a set of points, but with rounded corners. Yeah, you could use a spheresweep object, but that doesn’t use a constant radius unless you go with a linear sweep, but that doesn’t give the effect I want.

I worked out the math to define the location of the round, which looks correct. The math to define the rotation angle didn’t work out quite as well. I wonder whether it is rounding error?