While I was taking pics of the Dorstenia, I also looked at an old favorite of mine, Zygosicyos tripartitus (or Xerosicyos tripartitus) It is not in our database, yet!
I love the way this one gets all fat and round in Summer and really goes down in size during the Winter, when dormant and a lot less watered. Looking at the distance now between "bark" pieces, they are pretty much non-existent in Winter.