Here's a thought. We might ask a designer to put together the following three visual items, maybe as collage, maybe as partial superposition....
A picture of Riemann (could be small)
A very clear picture of figure 35.2 in our book, but cropped, so the 27 and the 32 doesn't appear: only the 29 and 31. The numerals 29 and the 3i could appear larger than in that figure, so they are unmistakable.
and as background one of the color pictures of the zeta-function taken from, say, Wikipedia.