This is a weird one. Using i,j,k for loop values is fine, especially tight inner loops. I can't see that ii,jj,kk adds anything. And I don't see much point in using verbose names like innerLoopIterator or arrayIdx or whatnot for these type of variables either.
Actually later on in rule 20 he implies (with negative logic of course) that i is actually a good inner loop variable name. So that's an inconsistency right there.
Actually later on in rule 20 he implies (with negative logic of course) that i is actually a good inner loop variable name. So that's an inconsistency right there.