diff --git a/src/oboy.ml b/src/oboy.ml
index 33f74be..785710d 100644
--- a/src/oboy.ml
+++ b/src/oboy.ml
@@ -1,8 +1,8 @@
 open Printf
 
-let rec run (cpu: Cpu.t) (mem: Memory.map) =
+let rec run (cpu: Cpu.t) (mem: Memory.map) (screen: Screen.t) =
   Cpu.run cpu mem;
-  run cpu mem
+  run cpu mem screen
 
 (** Power up sequence
     http://bgb.bircd.org/pandocs.htm#powerupsequence *)
@@ -16,7 +16,12 @@ let power_up cartridge =
 
     let cpu = Cpu.init_cpu in
     let mem = Memory.init cartridge in
-    run cpu mem
+    let screen = Screen.init in
+
+    Graphics.open_graph "";
+    Graphics.resize_window Screen.width Screen.height;
+
+    run cpu mem screen
 
 
 let () =
diff --git a/src/screen.ml b/src/screen.ml
index 43005a6..8f29776 100644
--- a/src/screen.ml
+++ b/src/screen.ml
@@ -1,14 +1,15 @@
+let width = 160
+let height = 144
+
 type pixel = {
-  r : char;
-  g : char;
-  b : char;
-  a : char;
+  r : int;
+  g : int;
+  b : int;
+  a : int;
 }
 
 type t = {
-  width  : int;
-  height : int;
-  data   : pixel array;
+  data   : pixel array array;
 }
 
 type control = {
@@ -45,11 +46,9 @@ let get_lcd_control mem =
     bg_display;
   }
 
-let init_screen w h =
+let init =
   {
-    width = w;
-    height = h;
-    data = Array.make_matrix h w { r = 255; g = 255; b = 255; a = 255 }
+    data = Array.make_matrix width height { r = 255; g = 255; b = 255; a = 255 }
   }