Succulent Rosette

I bought this big succulent from a garden visit some years ago. I am in the process of finding out its correct name, I promise! It's much larger than the sempervivums I've identified.

It lives in a rather small pot on the house patio, in a collection of other succulents. I enjoy their regular clean-ups, as the ever present wind deposits gum tree leaves all around them.

There's great mathematical form to appreciate in this plant, and it seems very well behaved and tidy throughout all seasons. More I cannot say!