There is another metaphor for this process of creating a structure which conveys, perhaps, something of the situation of the artist. He is very much like that classic figure of animated cartoons who ... is running along and, in complete concentration on his purpose-carried along, as it were, by the momentum of the act-runs right off the edge of a cliff without noticing it and continues running in mid-air until, looking down, he becomes aware of his unnatural situation, and in that moment, and because he perceives it as extraordinary and unnatural, is unable to sustain it, and falls.

So the artist, beginning in reality-in that which already exists- starts moving toward a vision, an Idea, and, with the cumulative momentum of that dedicated concentration, crosses the threshold from that which already exists into the void where, still moving forward, he creates a plane of earth where his foot has been, as the spider, spinning from his own guts, threads his ladders or highways through once empty space.

–– Maya Deren
Some Methaphors for the Creative Process