The “Geometrics” group of models starts with these two by the son of Lillian Oppenheimer: Bichromatic Square and Tripod. Both sets of diagrams are hand-drawn with hand-lettered instructions which I found a little hard to read.
I thought I remembered having seen the Bichromatic Square in the past, and I was right – the identical model is shown in “Origami for the Connoisseur” by Kunihiko Kasahara and Toshie Takahame, where it is called Coaster #1. It seems to have been independently invented by Toshikazu Kawasaki, and is used as a demonstration of what Kasahara calls “Iso-area folding.” By whatever name, it’s technically interesting to fold, but the resulting model is rather plain and won’t impress non-folders. Paper with contrasting colors on the two sides is essential; I used a 6″ square with blue and fuschia-red sides.
The Tripod’s instructions are in a very unusual format, with the first page having three columns which give the folding directions in verbal, geometric, and diagrammatic form. Folding presents no challenges. The creator recommends using the finished model as a stand (as shown above, right), or building modular models with it. I thought it needed some visual interest, so I used a 6″ square with a garish hexagonal print straight out of the Op-Art 1960’s.