[daveFNbuck]

I tried pasting the cross join and inner join into a colorblindness simulator [1] and the only issue I found is that the A and the 2 in the cross join look similar if you have monochromacy. Looking at the monochromatic version, I don't think this really affects the clarity of the cross join diagram.

The inner join is already perfectly distinguishable by how dark the squares are, and anything other than monochromacy preserves the distinctions that the color adds in the cross join, unless the site I used is misleading.

[1] https://www.color-blindness.com/coblis-color-blindness-simul...