Reever Knot
The reever knot is a secure and symmetrical way to join two ends of cordage.
Cross the two ends.
Bring right hand end under the cord and over itself.
Bring left hand end over two.
Bring that same end under one.
Bring the same end over itself and under one..
Then bring the same end through the bight at the right hand side of the knot.
Bring the other end through the bight at the other side of the knot.
Tighten.