Cubs: Have a demonstration setup and the lair must replicate it using a second set of ropes.
Scouts: Show the image or tell them the knots they must use to hang the log between the trees.
You’ll need four ropes of equal diameter, three six foot long, one twelve feet long. A two foot long log about six inches in diameter, and two trees 12-16 feet apart.
Thanks to scoutmastercg.com!