When I was a student in the 60s it was the 2 and 3 and it WAS a full circle. I sometimes spent a Sunday afternoon riding all the way round (nearly 2 hours).In this neck of the woods, the First 18 takes around two hours to get from central Sheffield to Hillsborough (around two miles away) - https://bustimes.org/services/18-sheffield-meadowhall#map - Sheffield has had various versions of an "outer circle" but generally without a western side to the circle, meaning the service ended up becoming more like a spiral (same with the old 2/59) due to the city's geography.
There seem to be more and more of these indirect routes and many are the result of local authorities combining separate routes to save money on retendering. As a result they are unattractive for end-to-end journeys but often with no direct alternative. The various incarnations of the Todmorden - Bacup - Rawtenstall service have included detours round housing estates, making for a tedious end to end journey. A colleague of mine used to refer to these as Heineken routes - they reach the parts other routes cannot reach!
