These doodles are mostly for stress relief for me plus training my hand after the time of many wrist inflammations due to strain. They were made from 2016 to now.
When I begin such a doodle I have no plan. All I know is that it will follow some rules how the edges are connected and what angles are allowed. So the doodle would just grow like a crystal. As you can see they also may vary in symmetry and number of axes - which also might be broken sometimes in favour of other patterns. That's what I call them, "Muster" - German for "patterns". This type of drawing is widely known as graph paper art. Which tock me until 2022 to find out... 🙂
I usually do these on 4-5mm squared paper. Some were made on a thin hexagon isometric 5mm grid or dot grid. Or on blank paper with a grid underneath on a light pad. Some are made colourfull by pencils including ones in neon and metallic, markers or just plain ink.