Corrugations

An arch is made stronger  with corrugations
furrows and grooves that are parallel
repeated as regular reiterations
keep the arch braced, stiff as well.

Blocks which overlap and interlock
create the furrows and the grooves
herringbone pattern of stacking block
to create masonry arch roofs.

Two receiving grooves are placed
on each block to receive rebar
with these grooves equally spaced
like strings are spaced on a guitar.

The rebar's curved in the diameter
of the arch of the masonry span
to provide supporting parameter
and scaffolding for the masonry man.