This hypothetical megastructure is depicted and explained on p.232 of Dymaxion World. The illustration shows a huge tetrahedral city floating in the San Francisco Bay, and Fuller remarks, significantly enough, that this structure would be earthquake-proof (such factors are included in Universal Requirements).
Part of what justifies describing this Floating City as "organic" is its potential for symmetrical enlargement. This is described in Synergetics (623.14) as the property of co-ordinate symmetry.
© Paul Taylor 2001