Found the definitive source from Pixar on Reyes, dicing, and micro polygons.

Quote - Micropolygons are the common basic geometric unit of the algorithm
(principle 3). They are flat-shaded quadrilaterals that are
approximately 1/2 pixel on a side. Since half a pixel is the
Nyquist limit for an image [6, 26], surface shading can be adequately
represented with a single color per micropolygon.

You can get the full paper here:

http://graphics.pixar.com/library/Reyes/

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