A diagram of the finite projective plane , a.k.a. Fano plane. (In this presentation of it, the labels are vectors over the finite field ; vectors on the same line are linearly dependent. Vectors whose third component is zero are “at infinity”, whereas the ones whose third component is one form a 2×2 array, suggestive of .)
Etymology
Named after Template:W (1871–1952), an Italian mathematician.