  Numerically computed with high accuracy are periodic traveling waves at the
free surface of a two dimensional, infinitely deep, and constant vorticity flow
of an incompressible inviscid fluid, under gravity, without the effects of
surface tension. Of particular interest is the angle the fluid surface of an
almost extreme wave makes with the horizontal. Numerically found are: (i) a
boundary layer where the angle rises sharply from $0^\circ$ at the crest to a
local maximum, which converges to $30.3787\dots^\circ$ as the amplitude
increases toward that of the extreme wave, independently of the vorticity, (ii)
an outer region where the angle descends to $0^\circ$ at the trough for
negative vorticity, while it rises to a maximum, greater than $30^\circ$, and
then falls sharply to $0^\circ$ at the trough for large positive vorticity, and
(iii) a transition region where the angle oscillates about $30^\circ$,
resembling the Gibbs phenomenon. Numerical evidence suggests that the amplitude
and frequency of the oscillations become independent of the vorticity as the
wave profile approaches the extreme form.
