code: function(oneaccidental) {
      var key = this.key(), limit = oneaccidental ? 2 : 3;
  
      return ['m3', 'm2', 'm-2', 'm-3']
        .map(this.interval.bind(this))
        .filter(function(note) {
        var acc = note.accidentalValue();
        var diff = key - (note.key() - acc);
  
        if (diff < limit && diff > -limit) {
          var product = vector.mul(knowledge.sharp, diff - acc);
          note.coord = vector.add(note.coord, product);
          return true;
        }
      });
    }
docs: Returns notes that are enharmonic with this note.