What were the runes and what did odin leave from the runes

The runes represented wisdom, and he gained wisdom through self sacrifice.

Stanza 138: " I know that I hung on a windy tree, nine long nights, wounded with a spear, dedicated to Odin, myself to myself, on that tree which no man knows from where it's roots run."

Stanza 139: "No bread did they give me nor drink from a horn, downwards I peered, I took the runes, screaming I took them, then I fell back from there."