diff --git a/go.mod b/go.mod
index 247fa01..89609a0 100644
--- a/go.mod
+++ b/go.mod
@@ -2,6 +2,5 @@ module github.com/vulcanize/go-eth-state-node-iterator
 
 go 1.13
 
-require github.com/ethereum/go-ethereum v1.10.9
-
-replace github.com/ethereum/go-ethereum v1.10.9 => github.com/vulcanize/go-ethereum v1.10.9-statediff-0.0.27
+require github.com/ethereum/go-ethereum v1.9.14
+replace github.com/ethereum/go-ethereum v1.9.14 => github.com/vulcanize/go-ethereum v1.10.14-statediff-0.0.29
diff --git a/iterator.go b/iterator.go
index 407ad24..80115de 100644
--- a/iterator.go
+++ b/iterator.go
@@ -112,14 +112,16 @@ func (gen *prefixGenerator) HasNext() bool {
 }
 
 func (gen *prefixGenerator) Next() {
+	// increment the cursor, and
 	gen.current[gen.stepIndex] += gen.step
 	overflow := false
 	for ix := 0; ix < len(gen.current); ix++ {
-		rix := len(gen.current) - 1 - ix // reverse
-		if overflow {
+		rix := len(gen.current) - 1 - ix // index in prefix is reverse
+		if overflow {                    // apply overflow
 			gen.current[rix]++
 			overflow = false
 		}
+		// detect overflow at this index
 		if rix != 0 && gen.current[rix] > 0xf {
 			gen.current[rix] = 0
 			overflow = true
diff --git a/iterator_test.go b/iterator_test.go
new file mode 100644
index 0000000..3a26f64
--- /dev/null
+++ b/iterator_test.go
@@ -0,0 +1,20 @@
+package iterator_test
+
+import (
+	"testing"
+
+	iter "github.com/vulcanize/go-eth-state-node-iterator"
+)
+
+func TestMakePaths(t *testing.T) {
+	var prefix []byte
+	for i := 0; i < 4; i++ {
+		nbins := uint(1) << i
+		paths := iter.MakePaths(prefix, nbins)
+		t.Log(paths)
+		if len(paths) != int(nbins) {
+			t.Logf("failed: TestMakePaths")
+			t.Error("wrong number of paths", len(paths))
+		}
+	}
+}