I recently came upon a model that had a fillet that was constant, but constantly two radii. I can't find the model, but I drew a sketch to indicate what I mean.

I drew this sketch pretty quickly, but this is basically a cross section of the fillet. An inspection of the curvature showed that the radius was constant in the two sections, but changed from one radius to the other at a specific point along the fillet. Is there some way to easily re-create this feature or was this created using lofts and other surfacing tools?

Thanks in advance for any help.