Islamic Art - Introduction to Fourfold Symmetry Shapes

To understand the technique of constructing Islamic patterns, we will begin with simple models, starting with quadruple division or four-fold radial symmetry.
Here bottom, some examples.
Look at the circles drawn in the top row: on the left side, the circle is divided into four parts, in the centre we divide it into eight parts (a multiple of 4) and in the next one to the right we have a circle with 16 divisions (also a multiple of 4).

Below the first row, we have circles containing some shapes that we can obtain starting from this four-fold symmetry.

Another way to analyze the designs is to see them as the result of overlapping shapes and their rotation over a common centre point to get symmetry, as shown in this short video.