The left image above shows a physical flow chart (Sankey diagram) made of 1000 sheets of paper. It was not meant to be directly read, but to be photographed (see right image). The physical apparatus, called Cosmograph, allowed people without graphic skills to easily produce nice-looking Sankey diagrams. It was copyrighted by IBM in 1933 and sold for $50. Sources: Willard Cope Brinton (1939) Graphic Presentation, p. 78. Jim Strickland (2012) Cosmograph? What's a Cosmograph?
1970 – 3D Sankey Diagram
This physical 3D Sankey diagram shows complex energy flows and was created in the 70s by the Center for Strategic & International Studies (CSIS). Little information is available about it. It seems to be composed of five layers of transparent sheet, with four additional layers running perpendicularly. Physical size unknown. Source: Energy Education References Wiki. Energy Flow Diagrams 1949-2009.