diff --git a/src/avalanche.rs b/src/avalanche.rs
new file mode 100644
index 0000000..939bfb0
--- /dev/null
+++ b/src/avalanche.rs
@@ -0,0 +1,40 @@
+type Mac = [u8; 6];
+
+pub fn debug () {
+	for input in [
+		[0, 0, 0, 0, 0, 0],
+		[0, 0, 0, 0, 0, 1],
+		[1, 0, 0, 0, 0, 0],
+		[1, 0, 0, 0, 0, 1],
+	] {
+		assert_eq! (unmix (mix (input)), input);
+	}
+	
+	println! ("Passed");
+}
+
+// NOT intended for any cryptography or security. This is TRIVIALLY reversible.
+// It's just to make it easier for humans to tell apart MACs where only a couple
+// numbers differ.
+
+fn mix (i: Mac) -> Mac {
+	[
+		i [0] ^ i [5],
+		i [1] ^ i [4],
+		i [2] ^ i [3],
+		i [3],
+		i [4],
+		i [5],
+	]
+}
+
+fn unmix (i: Mac) -> Mac {
+	[
+		i [0] ^ i [5],
+		i [1] ^ i [4],
+		i [2] ^ i [3],
+		i [3],
+		i [4],
+		i [5],
+	]
+}
diff --git a/src/main.rs b/src/main.rs
index 2495135..4e63554 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,7 @@
 use prelude::*;
 
 pub mod app_common;
+mod avalanche;
 mod client;
 mod ip;
 pub mod message;
@@ -31,6 +32,7 @@ async fn async_main () -> Result <(), AppError> {
 		Some ("--version") => println! ("lookaround v{}", LOOKAROUND_VERSION),
 		Some ("client") => client::client (args).await?,
 		Some ("config") => config (),
+		Some ("debug-avalanche") => avalanche::debug (),
 		Some ("find-nick") => client::find_nick (args).await?,
 		Some ("my-ips") => my_ips ()?,
 		Some ("server") => server::server (args).await?,