Studies of Euler diagrams/legato
This is one of the two 4-ary Boolean functions that have a multicrossing of all sets — the other being logota.
It has all possible spots except the intersection of no sets and of all sets. (Like foravo in two dimensions.)
As a sphere surface the Euler diagram has 6 square and 8 triangle cells, forming a spherical cuboctahedron. (So its graph forms a rhombic dodecahedron.)
The squares have weight 2. Eeach square borders two triangles with weight 1 and two with weight 3.
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