that (l value) comes from `l←≠v←𝕩` and `≠` comes from `(0<=)◶⟨1⋄0⊑≢⟩` and `◶ ← {𝕨((𝕨𝔽𝕩)⊑𝕘){𝔽}𝕩}`;
of those `⊑` is a simple `$x[$w]` lookup we've just seen, statement separators work, variable passthrough we tested earlier, trains are untested, and `≢` is `{param($x,$w) &$list $x.sh}` which is untested but simple;