diff --git a/interleave.hh b/interleave.hh
new file mode 100644
index 0000000..78c067e
--- /dev/null
+++ b/interleave.hh
@@ -0,0 +1,32 @@
+/*
+Interleavers
+
+Copyright 2023 Ahmet Inan <inan@aicodix.de>
+*/
+
+#pragma once
+
+namespace CODE {
+
+template <int SIZE, int ORDER, typename TYPE>
+static void Interleave(TYPE *out, const TYPE *in)
+{
+	static_assert(SIZE % ORDER == 0, "ORDER does not divide SIZE");
+	int LENGTH = SIZE / ORDER;
+	for (int i = 0; i < LENGTH; ++i)
+		for (int j = 0; j < ORDER; ++j)
+			out[ORDER*i+j] = in[i+j*LENGTH];
+}
+
+template <int SIZE, int ORDER, typename TYPE>
+static void Deinterleave(TYPE *out, const TYPE *in)
+{
+	static_assert(SIZE % ORDER == 0, "ORDER does not divide SIZE");
+	int LENGTH = SIZE / ORDER;
+	for (int i = 0; i < LENGTH; ++i)
+		for (int j = 0; j < ORDER; ++j)
+			out[i+j*LENGTH] = in[ORDER*i+j];
+}
+
+}
+