Of the little things I like about our 13th Age Gloranthabook, one of the silliest is how pages 347 and 348 look like they've been eaten by moths. It’s the oDarkness section of our runic geography chapter. oDarkness is the rune of the trolls, and trolls a) eat anything; and b) herd giant insects. So it always makes me happy that pages devoted to troll territories look like they’ve been nibbled by bugs!
But did I say this was silly? It’s not really. It’s the kind of thing Greg Stafford planned when he envisioned Glorantha’s runes. It’s more cosmic than it is accident.