Page 571 - Bob Holtzman "The Field Guide to Knots How to Identify, Tie, and Untie Over 80 Essential Knots for Outdoor Pursuits"

79. Diagonal Lashing

Most perpendicular structures require diagonal bracing to remain square:

without it, they’re likely to collapse parallelogram-wise. After lashing a
structure’s main horizontal and vertical members with Square Lashings, add
diagonal braces from corner to corner. Use Diagonal Lashings where the
diagonals cross verticals and horizontals, and where the diagonals cross
each other.

Instructions

1. Tie a Timber Hitch vertically around both poles, with both ends finishing up on top of the pole closer to
you and the long working end facing downward.

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