Rolled privacy fencing quickly begins the structural shape.
See the excellent work of César Añorveo to learn about Mexican design compost toilets, at this link. Over 100,000 compost toilets of César Añorveo's design are in Oaxaca with millions built throughout Mexico. You will need to use the back button of your browser if you wish to return to this site. Although César's work is in Spanish, there are sufficient photos and drawings for general comprehension by those who do not speak the language, includes a good source list for further research in English as-well-as Spanish.