Beamed-note lattice on a shared stave: diatonic (not chromatic) distance with a persistence gate

Two voices sharing a stave, both running beamed (sub-quarter) notes with opposing stems, in a close enough tessitura and for long enough, produce a visual lattice where the upper voice's beam and the lower voice's beam interleave through the middle of the staff — a collision that can occur even with ZERO simultaneous pitch crossings, because it is a product of the two voices' PITCH RANGES over a stretch of time, not their pitch order at any one instant.

Stone, Music Notation in the 20th Century, on independent-voice engraving and the case for one stave per part.

This rule needs the notated content and the rendered result together — the score says what should happen, the page says whether it did.