Having 2 different elements (i.e. surfaces) and repeating them
- layer caking
Having a hierarchy of forms, which are of different size. No two are allowed to be the same size actually.
- avoiding parallels
Having only lines that ... are not ... parallel
- also I wanted to repeat the shape on the left side in the design to have it look cohesive
- having fun, while drawing, which in my case meant that I allow myself to use the eraser tool and fiddle with the drawing
Hope you like it :)