**Although, in 1960, I had already exhibited a combinatory model of the five Platonic solids (later called the Metaeder) with van de Loo ; by restricting myself to packable solids at that time, my search for j, i.e. the golden section, the "Divina Proportione", the Fibonacci numbers, the harmonic series, and a pentagonal symmetry, was still in vain. I let the problem lie at the time, although it remained a constant challenge to me throughout the years.
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**Around 1980, I constructed a man-high Metaeder as an object of meditation and calculation. It consisted of a cube (edge length = 1m) with the tetrahedron and octahedron contained within it as packable regular solids, and the dodecahedron and icosahedron as regular solids circumscribing it.
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**The cube with the intracubic Platonic solids covered the field of packability, the extracubic solids being non-packable, though determined by the golden section in a wide variety of ways.
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**The Metaeder contains all basic geometric forms of modern structural architecture:
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**the cube with the right angle (or its deformations) stands for Mies van der Rohe ~1950**

**the tetrahedron- (semi-)octahedron- packing stands for Wachsmann and his "Hangar" ~1954**

**the combination of all packable Platonic solids, the integration of statics and utility, and the rotation of the lattices found in the different positions stands for Schulze-Fielitz 1959.**

**in the extracubic field, the truncated icosahedron with 20 hexagons and 12 pentagons as basic shapes in geodesics, as described in the patent of 1954, i.e. the Bucky-ball, one of the 13 Archimedean solids, stands for Buckminster Fuller ~1954**

**the diagonal plane in the icosahedron (and in the dodecahedron) are harmonic rectangles intersecting each other vertically, whose subdivision into the golden section produces harmonic series; all of these stand (scaled according to the human proportion) for the Le Corbusier's Modulor of 1951. The basic features of the Modulor are: golden series, rectangularity and human proportion.**

**Many structural discoveries in architecture were, more or less, made during the 1950's, a decade which we could call the incubation and blossoming period of the second (structural) modern architecture after the 1920's.
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**It is worthwhile to remember that the double helix (Watson and Crick 1953), quantum chemistry (Pauling) and structural anthropology (Lévi-Strauss 1958) were all discovered during this period.
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