diff --git a/Cargo.toml b/Cargo.toml
index 271a2c7..0f091e5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,5 +10,6 @@ edition = "2018"
 crate-type = ["cdylib"]
 
 [dependencies]
-"bitsy-parser" = "^0.71.1"
+"bitsy-parser" = "^0.72.0"
+"lazy_static"  = "^1.4.0"
 "wasm-bindgen" = "^0.2.64"
diff --git a/index.js b/index.js
index 8190e31..1cc751e 100644
--- a/index.js
+++ b/index.js
@@ -1,13 +1,27 @@
-import init, {merge} from './pkg/bitsy_merge.js';
+import init, {load_main, load_additional, merge} from './pkg/mixsy.js';
 
 async function run() {
     await init();
 
-    document.getElementById('merge').addEventListener('click', () => {
-        let a = document.getElementById('a').value;
-        let b = document.getElementById('b').value;
-        document.getElementById('c').value = merge(a, b);
-    })
+    const main         = document.getElementById('a');
+    const additional   = document.getElementById('b');
+    const output       = document.getElementById('c');
+    const merge_button = document.getElementById('merge');
+
+    main.addEventListener('change', () => {
+        console.debug(load_main(main.value));
+    });
+
+    additional.addEventListener('change', () => {
+        console.debug(load_additional(additional.value));
+    });
+
+    function mix() {
+        output.value = merge();
+    }
+
+    merge_button.addEventListener('click',    mix);
+    merge_button.addEventListener('touchend', mix);
 }
 
 run();
diff --git a/src/lib.rs b/src/lib.rs
index b9a26ff..9ecf6c0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,22 +1,48 @@
-use wasm_bindgen::prelude::*;
 use bitsy_parser::game::Game;
+use lazy_static::lazy_static;
+use std::sync::Mutex;
+use wasm_bindgen::prelude::*;
+
+struct State {
+    main:       Option<Game>,
+    additional: Option<Game>,
+}
+
+lazy_static! {
+    static ref STATE: Mutex<State> = Mutex::new(State { main: None, additional: None});
+}
+
+// TODO DEDUPE
 
 #[wasm_bindgen]
-pub fn merge(a: String, b: String) -> String {
-    let main = Game::from(a);
-    let additional = Game::from(b);
+pub fn load_main(game_data: String) -> String {
+    let game = Game::from(game_data);
 
-    if main.is_err() {
-        return "Couldn't parse main game.".to_string();
-    }
+    if game.is_ok() {
+        STATE.lock().unwrap().main = Some(game.unwrap());
+        "OK!"
+    } else {
+        "Could not parse game data"
+    }.to_string()
+}
 
-    if additional.is_err() {
-        return "Couldn't parse additional game.".to_string();
-    }
+#[wasm_bindgen]
+pub fn load_additional(game_data: String) -> String {
+    let game = Game::from(game_data);
 
-    let mut main = main.unwrap();
-    let additional = additional.unwrap();
+    if game.is_ok() {
+        STATE.lock().unwrap().additional = Some(game.unwrap());
+        "OK!"
+    } else {
+        "Could not parse game data"
+    }.to_string()
+}
 
+#[wasm_bindgen]
+pub fn merge() -> String {
+    let state = STATE.lock().unwrap();
+    let mut main = state.main.clone().unwrap();
+    let additional = state.additional.clone().unwrap();
     main.merge(additional);
     main.dedupe_tiles();
     main.to_string()