Corbelled courses at the top of the northern outer apse wall.
The intention here is to reduced the roof
gap to be spanned by gradually cantilevering out each successive
course of slabs. Until recently, it was thought that the temples were probably ultimately
roofed by long timbers
which were then sealed with a limestone plaster for waterproofing. In 2004 a
1/34th scale model of a temple with
a "generic" layout was constructed, and it was found that the apses
could be completely spanned with corbelling.
The number of courses required and the extra "counterbalancing"
material needed rather neatly produced a shape
that corresponded very well with contemporary clay models and carvings of
temples.