Playing chords using Lightpad blocks can be rather difficult. The Noise app does have a chord mode, but what’s produced are parallel block chords, all of the same type. On the desktop, there are some plugins or standalone software to transform note combinations into all sorts of chords and arpeggios (one note acting as almost a modifier key for the chord).
It’d make sense to have something like this on iOS. It could even work with two Lightpad blocks with one serving to change chords and the other Lightpad (or a Seaboard) to play the notes, a bit like a guitar or accordion. That way, complex chord structures (spanning multiple octaves) could be played much more easily.