Apparently, the two most common textbook metaphors for writing (USA)
are building a house (esp. a log cabin) and taking a journey. This
metaphors are applied to both process and product.
The house metaphor is too structured and linear: it implies that one
can draw up the blueprints (OUTLINE) and order the materials
(RESEARCH?) first, before starting contruction ("ACTUAL" WRITING),
that framing preceding plumbing, etc. The journey metaphor also
suggest more linearity than is typical of writers' processes and
implies that wandering (DIGRESSION?) is inefficient, perhaps even
that one knows the destination before starting out.