diff --git a/main.go b/main.go
index 9309b3d..6a7791e 100644
--- a/main.go
+++ b/main.go
@@ -56,7 +56,7 @@ func merge(cs ...<-chan int) <-chan int {
 	out := make(chan int)
 
 	go func() {
-		h := &IntHeap{}
+		h := &items{}
 		heap.Init(h)
 
 		// prime the pumps
@@ -89,28 +89,30 @@ func merge(cs ...<-chan int) <-chan int {
 	return out
 }
 
-// An IntHeap is a min-heap of ints.
-type IntHeap []item
+// item keeps track of an integer value and the index of its source.
+//
+// the index is used to chose the next source to use when a value has been
+// pulled.
+type item struct {
+	val int
+	src int
+}
 
-func (h IntHeap) Len() int           { return len(h) }
-func (h IntHeap) Less(i, j int) bool { return h[i].val < h[j].val }
-func (h IntHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+// items is a min-heap of item.
+type items []item
 
-func (h *IntHeap) Push(x interface{}) {
-	// Push and Pop use pointer receivers because they modify the slice's length,
-	// not just its contents.
+func (h items) Len() int           { return len(h) }
+func (h items) Less(i, j int) bool { return h[i].val < h[j].val }
+func (h items) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+
+func (h *items) Push(x interface{}) {
 	*h = append(*h, x.(item))
 }
 
-func (h *IntHeap) Pop() interface{} {
+func (h *items) Pop() interface{} {
 	old := *h
 	n := len(old)
 	x := old[n-1]
 	*h = old[0 : n-1]
 	return x
 }
-
-type item struct {
-	val int
-	src int
-}