diff --git a/enigma.ino b/enigma.ino
index c55272d..8fcca6e 100644
--- a/enigma.ino
+++ b/enigma.ino
@@ -34,21 +34,52 @@ Rotor rotors [] = {
   // id            name          wiring                        notch
   // ==            ====          ======                        =====
   {  "ABC",        "ABC",        "ABCDEFGHIJKLMNOPQRSTUVWXYZ", ""   },  //  0 alphabet
+
+  // 
   {  "I",          "I",          "EKMFLGDQVZNTOWYHXUSPAIBRCJ", "Q"  },  //  1 
   {  "II",         "II",         "AJDKSIRUXBLHWTMCQGZNPYFVOE", "E"  },  //  2
   {  "III",        "III",        "BDFHJLCPRTXVZNYEIWGAKMUSQO", "V"  },  //  3
   {  "IV",         "IV",         "ESOVPZJAYQUIRHXLNFTGKDCMWB", "J"  },  //  4
   {  "V",          "V",          "VZBRGITYUPSDNHLXAWMJQOFECK", "Z"  },  //  5
+
+  // 
   {  "VI",         "VI",         "JPGVOUMFYQBENHZRDKASXLICTW", "ZM" },  //  6
   {  "VII",        "VII",        "NZJHGRCXMYSWBOUFAIVLPEKQDT", "ZM" },  //  7
   {  "VIII",       "VIII",       "FKQHTLXOCBJSPDZRAMEWNIUYGV", "ZM" },  //  8
-  {  "beta",       "Beta",       "LEYJVCNIXWPBQMDRTAKZGFUHOS", ""   },  //  9
-  {  "gamma",      "Gamma",      "FSOKANUERHMBTIYCWLQPZXVGJD", ""   },  // 10
-  {  "UKW-A",      "UKW A",      "EJMZALYXVBWFCRQUONTSPIKHGD", ""   },  // 11 reflectors
+  {  "beta",       "Beta",       "LEYJVCNIXWPBQMDRTAKZGFUHOS", ""   },  //  9  M4 only
+  {  "gamma",      "Gamma",      "FSOKANUERHMBTIYCWLQPZXVGJD", ""   },  // 10  M4 only
+
+  // reflectors
+  {  "UKW-A",      "UKW A",      "EJMZALYXVBWFCRQUONTSPIKHGD", ""   },  // 11
   {  "UKW-B",      "UKW B",      "YRUHQSLDPXNGOKMIEBFZCWVJAT", ""   },  // 12
   {  "UKW-C",      "UKW C",      "FVPJIAOYEDRZXWGCTKUQSBNMHL", ""   },  // 13
-  {  "UKW-B-thin", "UKW B thin", "ENKQAUYWJICOPBLMDXZVFTHRGS", ""   },  // 14
-  {  "UKW-C-thin", "UKW C thin", "RDOBJNTKVEHMLFCWZAXGYIPSUQ", ""   }   // 15
+  {  "UKW-B-thin", "UKW B thin", "ENKQAUYWJICOPBLMDXZVFTHRGS", ""   },  // 14  M4 only
+  {  "UKW-C-thin", "UKW C thin", "RDOBJNTKVEHMLFCWZAXGYIPSUQ", ""   }   // 15  M4 only
+};
+
+
+typedef struct {
+  char *name;
+  char *description;
+  Rotor rotor_types[];
+  Rotor reflector_types[];
+} EnigmaType;
+
+EnigmaType enigma_types[] = {
+  { 
+    "M3",
+    "Army",
+    { rotors[1], rotors[2], rotors[3], rotors[4], rotors[5] },
+    { rotors[11], rotors[12] }
+  },
+  
+  { 
+    "M4",
+    "Navy",
+    // work out thin rotors
+    { rotors[1], rotors[2], rotors[3], rotors[4], rotors[5], rotors[6], rotors[7], rotors[8] },
+    { rotors[11], rotors[12] }
+  }
 };
 
 // entry wheel "EintrittswalzeEintrittswalze"
@@ -166,7 +197,8 @@ char encode (char c) {
   }
   pin = stridx(AZ, rotors[reflector_type].wiring[pin]);
   if (debug_mode) {
-    Serial.print("->"); Serial.print(AZ[pin]);
+    Serial.print("->");
+    Serial.print(AZ[pin]);
     Serial.print("  "); 
   }
   
@@ -248,8 +280,6 @@ void init_buf (char *buf) {
   }
 }
 
-// 01234
-
 void add_to_buf (char *buf, char c) {
   for (int i=0; i<BUF_SIZE-1; ++i) {
     buf[i] = buf[i+1];
@@ -296,15 +326,28 @@ void disp_plugboard () {
   }
 }
 
+// config:
+
+// reset
+// enigma type
+// for each rotor
+// - ringsetting
+// - rotor selection
+// plugboard
+// - clear
+// - set pair
+
 void setup () {
 //  Serial.begin(115200);
   kbd.begin();
   lcd.begin(LCD_COLS, LCD_ROWS);
 
   lcd.setCursor(0,1);
-  lcd.print("Enigma M3");
+  lcd.print("Enigma");
+  lcd.setCursor(0,2);
+  lcd.print("M3");
 
-//  test();
+  test();
   init_buf(input_buf);
   init_buf(encoded_buf);
   disp_rotors();
@@ -312,7 +355,10 @@ void setup () {
 }
 
 
-void loop () {
+bool demo_mode = false;
+bool config_mode = true;
+
+void enigma () {
   kbd.tick();
 
   while (kbd.available()) {
@@ -332,3 +378,42 @@ void loop () {
 
   delay(10);
 }
+
+void demo () {
+  
+}
+
+void config () {
+  // demo? y/n -> demo_mode
+  // enigma type? menu -> enigma_type
+  // rotor[
+}
+
+void loop () {
+  if (config_mode) {
+    config();
+  } else if (demo_mode) {
+    demo();
+  } else {
+    enigma();
+  }
+}
+
+
+/*
+  Eintrittwalze entry wheel (stator)
+  Greek wheels Beta and Gamma [for obvious reasons] used in the M4
+  Grundstellung ground setting
+  Ringstellung  ring setting
+  Stecker plug
+  Steckerbrett  plugboard [sometimes referred to as "Stecker board"]
+  Umkehrwalze reflector
+  Walzen  wheels
+  Walzenlage  wheel order
+ */
+
+ /*
+https://cryptocellar.org/Enigma/index.html
+http://www.mlb.co.jp/linux/science/genigma/enigma-referat/node4.html#SECTION00043000000000000000
+
+  */