rolled 59 = 59
>>17212925
here
Using purpose-crafted sticks, the Billu develop a crude runic alphabet. They are able to "read" the runes by bouncing sonar off of the arranged sticks, and recognizing the patterns the sticks are laid upon the ground in as words.
Words is a bit strong, the alphabet is short, and crude, and not capable of anything more than vague symbolism. It does however allow for the transmission of information, as the Billu begin to arrange "signs" on the ground that denote areas of danger, good hunting, or enemies.
Note: they cannot express detailed or literal ideas. For example, they have a runic symbol for "food", but no symbols that describe what type of food. The system also does not allow for numbers, as the concept of numbers is still foreign to the billu.
In common usage, runic signs are laid on the ground at the head of trails, and denote what lies on the path ahead. The system is vague, and easily disturbed by passing creatures, but it's a start.
Also note that the smaller Bellowers are not capable of understanding this, and prone to wandering through carefully laid signs unaware that the oddly specific patterns mean anything.