This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Voute.absidale.cathedrale.Paris. Vault de ViolletleDuc br Les projections des grandes votes du chur de la cathdrale de Paris que nous avons traces fig nous montrent en BDFG one vote presque carre compose de deux arcs ogives BG DF de deux arcs doubleaux BD FG d'un arc doubleau intermdiaire KI et de quatre formerets BK KF DI IG