
Kurokawa, Kisho - founder of metabolists 1960s Jpn
"cities that adapted to an ever-increasing population by building flexible, 'extendable' structures that could be added to over time."
"symbiosis in architectural terms to kurokawa meant that buildings shouldn’t be viewed as mechanical structures in isolation of each other but should instead work together advantageously as living, breathing entities".

Isozaki, Arata- metabolist architect;
Clusters in the Air in 1960-62 for Tokyo;
uses the same joint core system as he did for the City in the Air - see image below.

Other architects + city planners that are involved with this movement are Akri Shibuya, Youji Watanabe, Kenzo Tango, Kisho Kikutake, Takashi Asada, Noboru Kawazoe, Kiyonori Kikutake, Fumihiko Maki, Masato Otaka, Peter Cook, Ron Herron, Justus Dahinden Walter Jonas, Moshe Safdie and Gunther Domenig.
The following links are from a database of skyscrapers in the world today - with images of these;
http://skyscraperpage.com/diagrams/?searchID=40279594&offset=25
http://skyscraperpage.com/diagrams/?1178316.
For information of city block densities - I could use Urban Age website;
http://www.urban-age.net/10_cities/_data/data_UAC.html