Where the term comes from **A-flat sus two** appears in the video *Codex Taught Me How to Play Piano*, where a MIDI piano connected to a computer feeds what the player is noodling into an app built by Codex, which shows the notes on screen and names them — including chords like this one [^video]. The term is the app's label for a chord built on A-flat with a suspended second, surfacing during the player's noodling and turning an unplanned finger pattern into something the player can understand and dig into further.</Section><Section title="Why it matters here">It is an example of the channel's larger pattern: noodling at the keyboard becomes understanding when a tool reflects back what you just played. A chord name like A-flat sus two is the feedback loop made concrete — the same pattern the video suggests applying to any song, exercise, or technique you're curious about. No evidence in the captured material describes the chord's use in a specific song or exercise, so treat it here as a discovered chord label rather than a lesson on sus-two harmony. `- A-flat sus two is a chord name shown by the Codex-built piano app during MIDI noodling. - It illustrates how the app turns playing into understanding. - The captured material does not analyze the chord itself beyond its appearance as a label.