Quotation from: The Notebooks of Leonardo Da Vinci

Written by: Leonardo da Vinci

F. By chapels of still richer combinations, which necessitate an
octagon of larger dimensions:

Pl. XCI, No. 2 (MS. Ash. 11. 8b) [Footnote 2: The note accompanying
this plan is given under No. 754.]; on this plan the chapels
themselves appear to be central buildings formed like the first type
of the third group. Pl. LXXXVIII, No. 3.