Some time I will post some pictures of the Ad Quadratum design of the floor plan of my building.

But for now I have something else to talk about...

There is another method, even more ancient that these, of using geometry to lay out a building or to survey land, and this method has the good fortune of having actually survived into the present day, even in the West.

This method is mentioned by Herodotus as likely being the origin of geometry, it is the Egyptian practice of the Rope Stretchers. It was used by Egyptian officials to mark off land boundaries after the annual Nile floods (for taxation mostly, but it probably also prevented a lot of disputes) and they probably used it to build their buildings as well.

This system is very simple. There are 2 tools used to mark off or measure, a rope with knots at regular intervals and a plumb bob.

If the rope has 13 knots spaced at an equal distance, then it can be used in a number of ways. Perhaps most importantly it can be used to mark off perfect right angles by use of a 3-4-5 right triangle.

I have not experimented with this system, mostly because you need 3 people to do it right, but I imagine it would be much more limited than the other systems.

However, I can certainly see the use of a knotted rope as a simple method of transferring measurements from a drawing to a full size ground plan.

And Mo, you have the makings of a regular pentagon there in the second construction, it would appear.