The result holds no blocks and no inserts, only the entities they stood for, each transformed to where its reference put it. This is what a backend with no block of its own needs, and what draw.Drawing.plot and draw.Drawing.tikz do before rendering.

Blocks may contain inserts of other blocks and are expanded through. A block keeps its own definitions and inherits the enclosing drawing’s only for names it does not define itself.

A block cannot come to refer to itself: its drawing is captured by value when the block is defined, so redefining a name later cannot reach back into a definition already taken. The hundred-level limit is therefore a backstop against a construction this class does not permit, not a rule a caller can meet by accident.

See also: block, insert, draw.Drawing.entities

Source Code: draw.Drawing