Some piano to be found in hodgepodge of music notes, driving, genealogy, and crypto-currency.
- Functor -- Safeness, DrivingSpeed
- Applicative -- Safeness, DrivingTrip
- Monad -- Safeness, Crypto
- MaybeT -- Genealogy
- Recursion -- Triad
- Hidden constructor -- InstrumentMidiNum, Triad
- Pointfree style -- Triad