The Integral Thesis of Stafford Beer's Platform for Change as a composite System Diagram
Beer, Stafford (1975). Platform for change: A message from Stafford Beer. New York: Wiley.
I love this diagram. Beer's whole book - a series of talk transcripts from the first years of the 1970s - builds up to it and a series of theses/recommendations about how to change the world.
The diagram is a model of the past and future of the world (represented at the top and bottom). Most arrows indicate information flow--only the fat arrows show state transitions. Primarily the diagram shows the metasystems with which we discuss and stabilise existing systems.
What I like most about this diagram is that it regards both the past and future as 'present.' Our job is to, using the model, figure out how to put institutions, ethics, etc in the lower part of the diagram and not the top. (Though Beer warns about taking the model itself too seriously, calling models mistaken for reality 'surrogates'.)
Beer put his platform for change into practice, in part, in Chile with Cybersyn.