u/Cometpaw

I might be reading too far into it (though considering how it's Andy Weir we're talking about here, it's hard to read too far into anything scientific,) but it looks like each symbol is represented by the number of points on each one, almost in the shape of Eridian fingers for one through three. If anything, it makes the numbers infinitely easier to remember; Even before I thought of this, I memorized three and four by counting their points.