Sketch and floorplans of Reima & Raili Pietilä’s Kaleva Church in Tampere, 1964. Via.
Plan diagram of the “multi-cellular” geometry of the Lalin civic center, which is a complex series of interlocking and intersecting circles of various sizes that creates some stunning interior spaces (click for detail). Via.
Wenzel Jamnitzer - Perspectiva Corporum Regularium; studies on platonic solids and geometries, 1568(!). Via.
Wenzel Jamnitzer - Perspectiva Corporum Regularium; studies on platonic solids and geometries, 1568(!). Via.

I recently came across the above design by Hansjoerg Goeritz Architekturstudio for the National Parliment in Liechtenstein. While I think the design is interesting in its own right (and coincidentally, adjacent to one of my favorite museums), what I was primarily drawn to was the illustrative style of the project renderings.
While most likely drawn or enhanced digitally (Or not? Your thoughts?), the parallel axonometric vantage point and gentle shading does more the capture conceptual intent of the scheme more then a more photo-realistic rendering ever could. The abstracted representation of Vaduz Castle, home of the royal family, perched high on the adjacent hillside emphasizes the connection, both visually and civically, between the two governmental structures.
I also couldn’t help but be reminded of Rossi’s renderings from decades earlier, whose forms and styles were no doubt influential for Goeritz’s project:

Rendering for San Cataldo Cemetery, Moderna 1971. Via
Rossi’s rigid, pastel colored renderings were an important representational device to express the theoretical basis for his projects; the drawings themselves were able to convey the surreal and ethereal qualities that his buildings maintain in their built form. They work with a detached sense of reality by existing as a figment of the imagination while remaining unobtainably familiar; both severely grounded in their context and anomalistic in their presence.

Competition entry for a Regional Administrative Center, Trieste 1974. Via.
The drawings were crucial piece of postmodern architectural thought, neo-rational design, and Italian modernism. To read more there’s a great monograph devoted to his work available here.