diff --git a/right/src/default_layout.c b/right/src/default_layout.c
index e9db51e..0a53a15 100644
--- a/right/src/default_layout.c
+++ b/right/src/default_layout.c
@@ -1,77 +1,56 @@
 #include "default_layout.h"
 
-KEYBOARD_LAYOUT(defaultKeyboardLayout)={
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_7_AND_AMPERSAND } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F7 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_8_AND_ASTERISK } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F8 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_9_AND_OPENING_PARENTHESIS } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F9 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_0_AND_CLOSING_PARENTHESIS } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F10 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MINUS_AND_UNDERSCORE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F11 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_EQUAL_AND_PLUS } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F12 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_BACKSPACE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_DELETE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_U } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_I } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_UP_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_O } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_P } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_PRINT_SCREEN } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_OPENING_BRACKET_AND_OPENING_BRACE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_SCROLL_LOCK } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_CLOSING_BRACKET_AND_CLOSING_BRACE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_PAUSE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_BACKSLASH_AND_PIPE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_Y } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_PAGE_UP } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_J } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_K } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_DOWN_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_L } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_SEMICOLON_AND_COLON } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_APOSTROPHE_AND_QUOTE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_ENTER } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_H } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_PAGE_DOWN } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_N } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_MUTE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_M } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_COMMA_AND_LESS_THAN_SIGN } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_DOT_AND_GREATER_THAN_SIGN } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_SLASH_AND_QUESTION_MARK } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_SHIFT } }},
-        {Key_NoKey}, //??
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_SPACE } }},
-        {Key_NoKey}, //??
-        {{.type = UHK_KEY_LAYER, .layer = { .target = LAYER_FN }}}, //Fn
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_ALT } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_GUI } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_CONTROL } }},
+#define S(k) {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_ ## k }}
+#define L(l) {.type = UHK_KEY_LAYER, .layer = { .target = LAYER_ID_ ## l }}
+#define TRNS {.type = UHK_KEY_TRANSPARENT}
+
+#define Key_NoKey { .raw = 0 }
+
+KEYBOARD_LAYOUT(defaultKeyboardLayout)= {
+    // Layer 0
+    {
+        // Right
+        {
+            S(7_AND_AMPERSAND), S(8_AND_ASTERISK), S(9_AND_OPENING_PARENTHESIS), S(0_AND_CLOSING_PARENTHESIS), S(MINUS_AND_UNDERSCORE), S(EQUAL_AND_PLUS), S(BACKSPACE),
+            S(U), S(I), S(O), S(P), S(OPENING_BRACKET_AND_OPENING_BRACE), S(CLOSING_BRACKET_AND_CLOSING_BRACE), S(BACKSLASH_AND_PIPE), S(Y),
+            S(J), S(K), S(L), S(SEMICOLON_AND_COLON), S(APOSTROPHE_AND_QUOTE), S(ENTER), S(H),
+            S(N), S(M), S(COMMA_AND_LESS_THAN_SIGN), S(DOT_AND_GREATER_THAN_SIGN), S(SLASH_AND_QUESTION_MARK), S(RIGHT_SHIFT), Key_NoKey,
+            S(SPACE), L(MOD), L(FN), S(RIGHT_ALT), S(RIGHT_GUI), S(RIGHT_CONTROL),
+        },
+
+        // Left
+        {
+            S(GRAVE_ACCENT_AND_TILDE), S(1_AND_EXCLAMATION), S(2_AND_AT), S(3_AND_HASHMARK), S(4_AND_DOLLAR), S(5_AND_PERCENTAGE), S(6_AND_CARET),
+            S(TAB), S(Q), S(W), S(E), S(R), Key_NoKey, S(T),
+            S(CAPS_LOCK), S(A), S(S), S(D), S(F), Key_NoKey, S(G),
+            S(LEFT_SHIFT), S(NON_US_BACKSLASH_AND_PIPE), S(Z), S(X), S(C), S(V), S(B),
+            S(LEFT_CONTROL), S(LEFT_GUI), S(LEFT_ALT), L(FN), S(SPACE), L(MOD), Key_NoKey,
+        }
+    },
+
+    // Layer 1: MOD
+    {
+        // Right
+        {
+            S(F7), S(F8), S(F9), S(F10), S(F11), S(F12), S(DELETE),
+            Key_NoKey, S(UP_ARROW), Key_NoKey, S(PRINT_SCREEN), S(SCROLL_LOCK), S(PAUSE), Key_NoKey, S(PAGE_UP),
+            S(LEFT_ARROW), S(DOWN_ARROW), S(RIGHT_ARROW), Key_NoKey, Key_NoKey, Key_NoKey, S(PAGE_DOWN),
+            S(MEDIA_MUTE), Key_NoKey, Key_NoKey, Key_NoKey, Key_NoKey, Key_NoKey, Key_NoKey,
+            Key_NoKey, TRNS, Key_NoKey, Key_NoKey, Key_NoKey,
+        },
+
+        // Left
+        {
+            S(ESCAPE), S(F1), S(F2), S(F3), S(F4), S(F5), S(F6),
+            Key_NoKey, Key_NoKey, S(UP_ARROW), Key_NoKey, Key_NoKey, Key_NoKey, S(HOME),
+            Key_NoKey, S(LEFT_ARROW), S(DOWN_ARROW), S(RIGHT_ARROW), S(DELETE), Key_NoKey, S(END),
+            Key_NoKey, Key_NoKey, S(MEDIA_BACKWARD), S(MEDIA_PLAY), S(MEDIA_FORWARD), S(MEDIA_VOLUME_DOWN), S(MEDIA_VOLUME_UP),
+            Key_NoKey, Key_NoKey, Key_NoKey, Key_NoKey, Key_NoKey, TRNS, Key_NoKey,
+        }
+    },
+
+    // Layer 2: FN
+    // Layer 3: Mouse
 
-        //Left half
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_GRAVE_ACCENT_AND_TILDE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_ESCAPE } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_1_AND_EXCLAMATION } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F1 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_2_AND_AT } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F2 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_3_AND_HASHMARK } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F3 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_4_AND_DOLLAR } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F4 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_5_AND_PERCENTAGE } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F5 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_6_AND_CARET } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F6 } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_TAB } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_Q } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_W } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_UP_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_E } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_R } }},
-        {Key_NoKey}, //??
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_T } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_HOME } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_CAPS_LOCK } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_A } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_S } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_DOWN_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_D } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_RIGHT_ARROW } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_F } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_DELETE } }},
-        {Key_NoKey}, //??
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_G } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_END } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_SHIFT } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_NON_US_BACKSLASH_AND_PIPE } }}, //no idea if this is the right one},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_Z } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_BACKWARD } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_X } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_PLAY } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_C } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_FORWARD } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_V } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_VOLUME_DOWN } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_B } }, {.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_MEDIA_VOLUME_UP } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_CONTROL } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_GUI } }},
-        {{.type = UHK_KEY_SIMPLE, .simple = { .key = HID_KEYBOARD_SC_LEFT_ALT } }},
-        {{.type = UHK_KEY_LAYER, .layer = { .target = LAYER_FN }}}, //Fn
-        {Key_NoKey}, //??
-        {{.type = UHK_KEY_LAYER, .layer = { .target = LAYER_MOD }}}, //Mod
-        {Key_NoKey} //??
 };
 
diff --git a/right/src/keyboard_layout.c b/right/src/keyboard_layout.c
index 79de692..c2aa002 100644
--- a/right/src/keyboard_layout.c
+++ b/right/src/keyboard_layout.c
@@ -1,22 +1,22 @@
 #include "keyboard_layout.h"
 #include "led_driver.h"
 
-static uint8_t keyMasks[LAYOUT_KEY_COUNT];
+static uint8_t keyMasks[SLOT_COUNT][MAX_KEY_COUNT_PER_MODULE];
 static uint8_t modifierState = 0;
 
-static inline __attribute__((always_inline)) uhk_key_t getKeycode(KEYBOARD_LAYOUT(layout), uint8_t keyId)
+static inline __attribute__((always_inline)) uhk_key_t getKeycode(KEYBOARD_LAYOUT(layout), uint8_t slotId, uint8_t keyId)
 {
-    if (keyId < LAYOUT_KEY_COUNT) {
-        if (keyMasks[keyId]!=0 && keyMasks[keyId]!=modifierState) {
+    if (keyId < MAX_KEY_COUNT_PER_MODULE) {
+        if (keyMasks[slotId][keyId]!=0 && keyMasks[slotId][keyId]!=modifierState) {
             // Mask out key presses after releasing modifier keys
             return (uhk_key_t){.raw=0};
         }
 
-        uhk_key_t k = layout[keyId][modifierState];
-        keyMasks[keyId] = modifierState;
+        uhk_key_t k = layout[modifierState][slotId][keyId];
+        keyMasks[slotId][keyId] = modifierState;
 
         if (k.raw == 0) {
-            k = layout[keyId][0];
+            k = layout[0][slotId][keyId];
         }
 
         return k;
@@ -27,13 +27,13 @@ static inline __attribute__((always_inline)) uhk_key_t getKeycode(KEYBOARD_LAYOU
 
 static void clearKeymasks(const uint8_t *leftKeyStates, const uint8_t *rightKeyStates){
     int i;
-    for (i=0; i<KEY_STATE_COUNT; i++){
+    for (i=0; i < MAX_KEY_COUNT_PER_MODULE; i++){
         if (rightKeyStates[i]==0){
-            keyMasks[i] = 0;
+            keyMasks[SLOT_ID_RIGHT_KEYBOARD_HALF][i] = 0;
         }
 
         if (leftKeyStates[i]==0) {
-            keyMasks[LAYOUT_LEFT_OFFSET+i] = 0;
+            keyMasks[SLOT_ID_LEFT_KEYBOARD_HALF][i] = 0;
         }
     }
 }
@@ -96,7 +96,7 @@ void fillKeyboardReport(usb_keyboard_report_t *report, const uint8_t *leftKeySta
             break;
         }
 
-        uhk_key_t code = getKeycode(layout, keyId);
+        uhk_key_t code = getKeycode(layout, SLOT_ID_RIGHT_KEYBOARD_HALF, keyId);
 
         if (handleKey(code, scancodeIdx, report, rightKeyStates[keyId])) {
             scancodeIdx++;
@@ -108,7 +108,7 @@ void fillKeyboardReport(usb_keyboard_report_t *report, const uint8_t *leftKeySta
             break;
         }
 
-        uhk_key_t code = getKeycode(layout, LAYOUT_LEFT_OFFSET+keyId);
+        uhk_key_t code = getKeycode(layout, SLOT_ID_LEFT_KEYBOARD_HALF, keyId);
 
         if (handleKey(code, scancodeIdx, report, leftKeyStates[keyId])) {
             scancodeIdx++;
diff --git a/right/src/keyboard_layout.h b/right/src/keyboard_layout.h
index 662f070..f2d469c 100644
--- a/right/src/keyboard_layout.h
+++ b/right/src/keyboard_layout.h
@@ -5,6 +5,8 @@
 #include "lufa/HIDClassCommon.h"
 #include "usb_composite_device.h"
 
+#include "module.h"
+
 // Keyboard layout is a 2D array of scan codes.
 //
 // First dimension is the Key ID of a given key. Key IDs are the indices of the
@@ -33,6 +35,8 @@ typedef enum {
     UHK_KEY_MACRO,
     UHK_KEY_LPRESSMOD,
     UHK_KEY_LPRESSLAYER,
+
+    UHK_KEY_TRANSPARENT = 0xff,
 } uhk_key_type_t;
 
 typedef union {
@@ -76,11 +80,7 @@ typedef union {
     uint32_t raw;
 } __attribute__ ((packed)) uhk_key_t;
 
-#define Key_NoKey {.raw = 0}
-#define KEYBOARD_LAYOUT(name) const uhk_key_t name[LAYOUT_KEY_COUNT][LAYOUT_MOD_COUNT]
-
-#define LAYER_MOD 1
-#define LAYER_FN 2
+#define KEYBOARD_LAYOUT(name) uhk_key_t name[LAYER_COUNT][SLOT_COUNT][MAX_KEY_COUNT_PER_MODULE]
 
 void fillKeyboardReport(usb_keyboard_report_t *report, const uint8_t *leftKeyStates, const uint8_t *rightKeyStates, KEYBOARD_LAYOUT(layout));