Harpedonaptai are more commonly known as the "Rope Stretchers" or the "Rope Knotters".They were employed by the Pharaohs as a land surveyors. They used to form right angles with their ropes. Some scholars conjectured, that they may have constructed right angles by using a rope consisting of 12 equidistant knots. Such a rope can be spanned into 345 triangle, which has a right angle according the converse of Pythagorean theorem.
