the 4 building blocks of drawings, they can be used as guides for other building blocks or exist in and of themselves

1. Lines
Lines connect things together, they can also be drawn arbitrarily if they reference some culturally established symbol (i.e a heart). Their simplicity makes them excellent guides for the most complex objects (i.e folding clothes, hair)
2. Planes
Planes are the second easiest to draw
3. Hard forms
The most difficult to draw, they are multiple planes bound together
4. Soft forms
Their form is not defined by their outer shape, rather it's how things are placed in relation to them (or on them) that they start to make sense in 3d space