//! **Why a channel could not carry a gesture** (DESIGN §3.8) — the two
//! classes that differ in what to do next, kept apart from the channel that
//! produces them because a classification is not a conversation.
/// **Why a channel could not carry a gesture** — in the two classes that
/// differ in what to do next, and in nothing else.
///
/// The split is drawn from *what failed*, never from the sentence: a foot that
/// decided its own lifetime by reading prose would be a foot the far end could
/// rewrite by rewording.