But since the growth of perception, like the power of graphic representation, is gradual and partial, though progressive, the eye and the mind are generally first impressed with the salient features and leading characteristics of natural forms, just as the child's first idea of a human form is that of a body with four straight limbs, with a preponderating head. That is the first impression, and it is unhesitatingly recorded in infantine outline.
The first aim, then, in drawing anything in line is to grasp the general truths of form, character, and expression.
The Progressive Method
There are various methods of proceeding in getting an outline of any object or figure. To begin with, the student might begin progressively defining the form by a series of stages in this way. Take the profile of a bird, for instance; the form might be gradually built up by the combination of a series of lines:
or take the simpler form of a flask bottle:
or a jar on the same principle: