One of Haeckel's many drawings of the skeletons of radiolarians, tiny one-celled marine organisms with fantastic varieties of form.
  • Salingaros, Nikos A., and Michael W. Mehaffy. "Ch 17. Alexander’s Sustainable Technology" In Design for a Living Planet: Settlement, Science, & the Human Future. Design for a Living Planet: Settlement, Science, & the Human Future. Levellers/Sustasis Press and Vajra Publications, 2015. Digital Library