diff --git a/src/testdata/chord_progressions.txt b/src/testdata/chord_progressions.txt
index eff1730..275fb5e 100644
--- a/src/testdata/chord_progressions.txt
+++ b/src/testdata/chord_progressions.txt
@@ -1,9 +1,12 @@
+# x+0 x+5 x+7 x+0
 CM0 CM3 CM4 CM0
 
 .
 
+# x+2 x+7 x+0
 CM1 CM4 CM0
 
 .
 
+# x+0 x+7 x+9 x+5
 CM0 CM4 CM5 CM3
diff --git a/src/testdata/fifth_wheel.txt b/src/testdata/fifth_wheel.txt
index a3b7bf6..78a25e1 100644
--- a/src/testdata/fifth_wheel.txt
+++ b/src/testdata/fifth_wheel.txt
@@ -1,4 +1,4 @@
-# fifth wheel = :shrug:
+# fifth wheel = +7 semitones
 # f -> c -> g -> d -> a -> e -> b
 
 f c g d a e b