Here's a weird relationship between consecutive primes that I discovered while bored trying some python... Take the last digit (in base 10) of consecutive prim

Here's a weird relationship between consecutive primes that I discovered while bored trying some python... Take the last digit (in base 10) of consecutive primes. Now ignore 2 and 5 as .. well they only occur once, and look at the mapping between 1->3, 1->5, 1->7, 1->9 ... 3->1 etc etc.. You would think that they would pretty much all be equal, I mean primes are "random" right? WRONG! There are statistically significant differences in those edges, and no-one knows why.