diff --git a/src/music.clj b/src/music.clj
index e1832b8..13c97c4 100644
--- a/src/music.clj
+++ b/src/music.clj
@@ -70,13 +70,16 @@
     :Abb 7 :Ab 8 :A 9 :A# 10 :A## 11
     :Bbb 9 :Bb 10 :B 11 :B# 12 :B## 13))
 
-(defn abs-pitch [pitch-class octave]
+(defn abs-pitch
   "Returns the absolute pitch of a pitch class at an octave"
-  (+ (* 12 octave) (pc-to-int pitch-class)))
+  ([pitch-class octave] (abs-pitch [pitch-class octave]))
+  ([[pitch-class octave]]
+   (+ (* 12 octave) (pc-to-int pitch-class))))
 
-(defn pitch [abs-pitch]
+(defn pitch 
   "Returns the pitch class and octave represented by the absolute pitch.
    In cases of enharmonic equivalence, returns the sharp rather than the flat."
+  [abs-pitch]
   (let [scale [:C :C# :D :D# :E :F :F# :G :G# :A :A# :B]
         octave (quot abs-pitch 12)
         index (rem abs-pitch 12)]
@@ -85,8 +88,24 @@
 (defn trans [n [pitch-class octave]]
   (pitch (+ (abs-pitch pitch-class octave) n)))
 
-(defn line [[m & ms :as music]]
+(defn line 
   "Combines musics via the sequential (:+) operator"
-  (if (nil? (seq music))
+  [[m & ms :as musics]]
+  (if (nil? (seq musics))
     (rest 0)
     [:+ m (line ms)]))
+
+(defn chord 
+  "Combines musics via the simultaneous (:=) operator"
+  [[m & ms :as musics]]
+  (if (nil? (seq musics))
+    (rest 0)
+    [:= m (line ms)]))
+
+(defn max-pitch [[p & ps :as pitches]]
+  (if (nil? (seq pitches))
+    (pitch 0)
+    (let [max-ps (max-pitch ps)]
+      (if (> (abs-pitch p) (abs-pitch max-ps))
+       p
+       max-ps))))