The corbel vault
A Maya corbel (“false”) vault: courses stepping inward until a capstone closes the gap. It is stable only while each half’s centre of gravity stays over its wall.
The rules it illustrates
Keep each half of a corbel vault over its wall. In a corbelled vault each course may project only a little beyond the one below, and each overhanging half must have its centre of gravity behind the inner face of its wall; load the tails of the stones with heavy hearting until the capstone is set.
Corbelled rooms are narrow. Keep the span of a corbelled room to about three metres or less and make it long instead of wide; to enlarge a building, add parallel galleries rather than widening them.
Where it appears in the book
In the styles Mesoamerican.
In the chapters Post and Lintel, The Americas.