Incidence structure of the Fano plane
Points have binary weights 1, 2 or 3. They are used to label groups of similar points and lines.

The full and empty set are instead labeled with the symbols for true and false: ⊤ ⊥
Own work
WatchduckYou can name the author as "T. Piesk", "Tilman Piesk" or "Watchduck".