pcolor - color values argument



matplotlib.pyplot.pcolor(*args, **kwargs)

Create a pseudocolor plot of a 2-D array.

C is the array of color values.

I tried to see how can I map custom color values to example array, but
seems hard to understand.
I created 2x2 mesh, and appropriate C array for it. Changing values in
this C array changes colors on plotted mesh in what it seems irregular

Does C array map colors from default colormap? If yes, in which way
they are plotted according values in this C array?
Or how can I tell matplotlib to use "this" RGB value for "this" cell
in a mesh, then another RGB value for other cell and so on