The Neural Control of Vision
O. Illusions

3a. The effect can be negated without affecting the assumed
relationship between the stimulus and the receptive fields

hermann grid illusion - wavy lines

Center/surround antagonism in retinal ganglion cells should be the same at the intersections
in these four figures. Yet the smudges are mostly non-existent in B-D.

hermann grid illusion - edge variations

Variations of panels B and D published by Janos Geier, can be viewed at the following links:
Sinusoidal grid
Waved grid