Which phrases copy from a region holding position 100

Which phrases copy from a region holding position 100

Every copying phrase of a 2,048-character collection, drawn as the interval of text it copies FROM, sorted by where that interval starts. The vertical rule is one occurrence already found; a phrase produces a new occurrence exactly when its source interval contains the whole of it, which is 1 of the 137 phrases here. The walk this collection shipped examines every phrase whose source starts at or before the rule — the whole upper part of the picture — and the grid asks for the two-sided condition directly.

Drawn at 700 × 567, wide on the page. Everything above is what grid-propagation returns with no arguments; the caption is the generator's own, computed from the numbers in the drawing rather than written beside it.

4 essays call grid-propagation. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about — which is what optcheck and figfill exist to catch.