diff --git a/tape/dynamic.go b/tape/dynamic.go
index e56da67..ae2981c 100644
--- a/tape/dynamic.go
+++ b/tape/dynamic.go
@@ -6,6 +6,8 @@ package tape
 // TODO: add support for struct tags: `tape:"0000"`, tape:"0001"` so they can get
 // transformed into tables with a defined schema
 
+// TODO: test all of these smaller functions individually
+
 import "fmt"
 import "reflect"
 
@@ -346,10 +348,12 @@ func peekSlice(decoder *Decoder, tag Tag) (Tag, int, error) {
 	for {
 		elem, populated, n, err := peekSliceOnce(decoder, tag, offset)
 		if err != nil { return 0, 0, err }
-		offset    += n
+		offset     = n
 		dimension += 1
 		if elem.Is(OTA) {
 			if !populated {
+				// default to a large byte array, will be
+				// interpreted as a string.
 				return LBA, dimension + 1, nil
 			}
 		} else {
@@ -371,7 +375,7 @@ func peekSliceOnce(decoder *Decoder, tag Tag, offset int) (elem Tag, populated b
 	headerBytes, err := decoder.Peek(elemTagEnd)
 	if err != nil { return 0, false, 0, err }
 
-	elem = Tag(headerBytes[len(headerBytes)])
+	elem = Tag(headerBytes[len(headerBytes) - 1])
 	for index := lengthStart; index < lengthEnd; index += 1 {
 		if headerBytes[index] > 0 {
 			populated = true
diff --git a/tape/dynamic_test.go b/tape/dynamic_test.go
index 274bf46..fbbea68 100644
--- a/tape/dynamic_test.go
+++ b/tape/dynamic_test.go
@@ -67,6 +67,65 @@ func TestEncodeDecodeAnyMap(test *testing.T) {
 	if err != nil { test.Fatal(err) }
 }
 
+func TestPeekSlice(test *testing.T) {
+	buffer := bytes.NewBuffer([]byte {
+		2, byte(OTA.WithCN(3)),
+		0, 0, 0, 1, byte(LI.WithCN(1)),
+		0, 0x5,
+		2, byte(LI.WithCN(1)),
+		0,    0x17,
+		0xAA, 0xAA,
+	})
+	decoder := NewDecoder(buffer)
+
+	elem, dimension, err := peekSlice(decoder, OTA.WithCN(0))
+	if err != nil { test.Fatal(err) }
+	if elem != LI.WithCN(1) {
+		test.Fatalf("wrong element tag: %v %02X", elem, byte(elem))
+	}
+	if got, correct := dimension, 2; got != correct {
+		test.Fatalf("wrong dimension: %d != %d", got, correct)
+	}
+}
+
+func TestPeekSliceOnce(test *testing.T) {
+	buffer := bytes.NewBuffer([]byte {
+		2, byte(OTA.WithCN(3)),
+		0, 0, 0, 1, byte(LI.WithCN(1)),
+		0, 0x5,
+		2, byte(LI.WithCN(1)),
+		0,    0x17,
+		0xAA, 0xAA,
+	})
+	decoder := NewDecoder(buffer)
+
+	test.Log("--- stage 1")
+	elem, populated, n, err := peekSliceOnce(decoder, OTA.WithCN(0), 0)
+	if err != nil { test.Fatal(err) }
+	if elem != OTA.WithCN(3) {
+		test.Fatal("wrong element tag:", elem)
+	}
+	if !populated {
+		test.Fatal("wrong populated:", populated)
+	}
+	if got, correct := n, 2; got != correct {
+		test.Fatalf("wrong n: %d != %d", got, correct)
+	}
+	
+	test.Log("--- stage 2")
+	elem, populated, n, err = peekSliceOnce(decoder, elem, n)
+	if err != nil { test.Fatal(err) }
+	if elem != LI.WithCN(1) {
+		test.Fatal("wrong element tag:", elem)
+	}
+	if !populated {
+		test.Fatal("wrong populated:", populated)
+	}
+	if got, correct := n, 7; got != correct {
+		test.Fatalf("wrong n: %d != %d", got, correct)
+	}
+}
+
 func encAny(value any) ([]byte, Tag, int, error) {
 	tag, err := TagAny(value)
 	if err != nil { return nil, 0, 0, err }