Here are a few of a pair of fluorescent tubes I pulled out of a job 2 weeks ago.. I am not sure how old they are but I know the manufacturer is not around anymore.. I guess these were similar to those " power groove" fluorescent lamps that were made many moons ago.
I seem to remember high-UV output fluorescents that looked like this - circa early 90's or late 80's. I imagine they had some weak spots on the "sharp" edges around the twists that would cause them to break when tapped against an edge of a table or something. Although they look kinda neat, the shape kind of defeats the strength of the cylindrical design.