To give you an idea of what the calculations would be like... let a, b, and c be the proportions of black in each of the three panels (ie a=b=c=0 would be a completely white image, a=b=c=1 would be a completely black image... (a+b+c)/3 is the proportion of black in the whole image, since the three panels are the same size).
Now, we have:
a = ((number of black pixels in panel border, labels and circle around pie chart) + (area inside pie chart) * (a+b+c)/3) / area of panel
b = ((number of black pixels in panel border, labels and axes) + (a+b+c)*(width of bars)*(constant representing vertical scale of graph)) / area of panel
c = ((number of black pixels in panel border, labels and axes) + (a+b+c)/3*(scale of shrunken copy of image)) / area of panel
This is three linear equations in three unknowns, which you can solve to get the three values. Then you can draw the two graphs, and then repeatedly copy-and-scale-down the whole picture to make the third panel (which you'd continually do until the scaled-down-third-panel-in-the-scaled-down-third-panel-in-the-etc-etc-in-the-comic is less than a pixel in size).
Zozoped: be careful not to confuse "the limit of the series is 2" with "the series will eventually reach 2"... the former is true, the latter is false. 0.999...=1, but this sequence never reaches 0.999... .
However, for clarity, "the series will never exceed 2" still gets the point across, and avoids confusion involving the limit. After all, it is the limit we're concerned with here in the actual comic (well, actually, we want the fixed point of the self-description... it just happens that all of the self-description things are contracting (that is, updating each graph to reflect adding x pixels involves adding fewer than x pixels), so if we take it as a recurrence relation, it will eventually converge towards that fixed point).
While no one overhear you quickly tell me not cow cow.
but how about watch phone?