diff --git a/pedro/snake/snake.ino b/pedro/snake/snake.ino
deleted file mode 100644
index 4e98e7d..0000000
--- a/pedro/snake/snake.ino
+++ /dev/null
@@ -1,153 +0,0 @@
-#define BOARD_LENGTH 8
-
-struct pair {
-  int x;
-  int y;
-};
-
-class Snake {
-private:
-  char state;
-  int snake_size;
-  pair pos[64];
-  pair get_next_move(pair p);
-
-public:
-  Snake() {
-    this->state = 'U';
-    this->snake_size = 4;
-    for (int i = snake_size - 1; i >= 0; i--) {
-      pair p;
-      p.x = 5;
-      p.y = i;
-      this->pos[i] = p;
-    }
-  }
-  void change_state(char m);
-  void eat(pair p);
-  void snake_to_matrix(int (*pixels)[BOARD_LENGTH]){
-    for(int i = 0; i < BOARD_LENGTH; i++){
-      for(int j = 0; j < BOARD_LENGTH; j++){
-        pixels[i][j] = HIGH; // CLEAR ALL PIXELS;
-      }
-    }
-    for(int i = 0; i < snake_size; i++) {
-      pair p = pos[i];
-      pixels[p.x][p.y] = LOW; // TURN ON PIXELS OF SNAKE
-    }
-  }
-  void next_move();
-  pair snake_head() {
-    return pos[0];
-  }
-};
-
-pair Snake::get_next_move(pair p) {
-  pair r;
-  switch (state) {
-  case 'U':
-    r.x = (p.x + BOARD_LENGTH - 1) % BOARD_LENGTH;
-    r.y = p.y;
-    break;
-  case 'D':
-    r.x = (p.x + 1) % BOARD_LENGTH;
-    r.y = p.y;
-    break;
-  case 'L':
-    r.x = p.x;
-    r.y = (p.y + 1) % BOARD_LENGTH;
-    break;
-  case 'R':
-    r.x = p.x;
-    r.y = (p.y + BOARD_LENGTH - 1) % BOARD_LENGTH;
-    break;
-  }
-  return r;
-}
-
-void Snake::next_move() {
-  for (int i = snake_size; i > 0; i--) {
-    pos[i] = pos[i - 1];
-  }
-  pos[0] = get_next_move(pos[0]);
-}
-
-void Snake::eat(pair p) { pos[snake_size++] = p; }
-
-const int row[8] = {2, 7, 19, 5, 13, 18, 12, 16};
-
-// 2-dimensional array of column pin numbers:
-const int col[8] = {6, 11, 10, 3, 17, 4, 8, 9};
-
-// 2-dimensional array of pixels:
-int pixels[8][8];
-
-// cursor position:
-int x = 5;
-int y = 5;
-Snake snake;
-
-void setup() {
-  // initialize the I/O pins as outputs
-  // iterate over the pins:
-  for (int thisPin = 0; thisPin < 8; thisPin++) {
-    // initialize the output pins:
-    pinMode(col[thisPin], OUTPUT);
-    pinMode(row[thisPin], OUTPUT);
-    // take the col pins (i.e. the cathodes) high to ensure that
-    // the LEDS are off:
-    digitalWrite(col[thisPin], HIGH);
-  }
-
-  // initialize the pixel matrix:
-  for (int x = 0; x < 8; x++) {
-    for (int y = 0; y < 8; y++) {
-      pixels[x][y] = HIGH;
-    }
-  }
-}
-
-void loop() {
-  // read input:
-  // readSensors();
-  snake.snake_to_matrix(pixels);
-  snake.next_move();
-  // draw the screen:
-  for(int i = 0; i < 100; i++)
-    Display();
-}
-
-void readSensors() {
-  // turn off the last position:
-  pixels[x][y] = HIGH;
-  // read the sensors for X and Y values:
-  x = 7 - map(analogRead(A0), 0, 1022, 0, 7);
-  y = map(analogRead(A1), 0, 1022, 0, 7);
-  // set the new pixel position low so that the LED will turn on
-  // in the next screen refresh:
-  pixels[x][y] = LOW;
-}
-
-void Display()    
-{  
-  for(int c = 0; c<8;c++)  
-  {  
-    digitalWrite(col[c],LOW);//use thr column 
-    //loop
-    for(int r = 0;r<8;r++)  
-    {  
-      digitalWrite(row[r],(pixels[r][c]+1)%2);  
-    }  
-    delay(1);  
-    Clear();  //Remove empty display light
-  }  
-}  
-  
-void Clear()                          //清空显示  
-{  
-  for(int i = 0;i<8;i++)  
-  {  
-    digitalWrite(row[i],LOW);  
-    digitalWrite(col[i],HIGH);  
-  }  
-} 
diff --git a/snake.ino b/snake.ino
index 984d855..2755b25 100644
--- a/snake.ino
+++ b/snake.ino
@@ -2,117 +2,128 @@
 #define SNAKE_MAX_SIZE 32
 
 struct pair {
-  int x;
-  int y;
+        int x;
+        int y;
 };
 
 class Snake {
-private:
-  char state;
-  int snake_size;
-  pair pos[64];
-  pair get_next_move(pair p);
-  pair fruitPos;
-  bool fruit;
+ private:
+        char state;
+        int snake_size;
+        pair pos[64];
+        pair get_next_move(pair p);
+        pair fruit_pos;
+        bool fruit;
 
-public:
-  Snake() {
-    this->state = 'U';
-    this->snake_size = 4;
-    fruit = false;
-    for (int i = snake_size - 1; i >= 0; i--) {
-      pair p;
-      p.x = 5;
-      p.y = i;
-      this->pos[i] = p;
-    }
-  }
-  void change_state(char state) {
-    if (state != '\0'){
-      if((state == 'L' || state == 'R') && (this->state == 'U' || this->state=='D')) // if currently moving up or down and state change is left or right update
-        this->state = state;
-      else if((state == 'U' || state == 'D') && (this->state == 'L' || this->state=='R')) // the opposite
-        this->state = state;
-    }
-    //else ignore    
-  }
-  void grow();
-  void snake_to_matrix(int (*pixels)[BOARD_LENGTH]){
-    for(int i = 0; i < BOARD_LENGTH; i++){
-      for(int j = 0; j < BOARD_LENGTH; j++){
-        pixels[i][j] = HIGH; // CLEAR ALL PIXELS;
-      }
-    }
-    for(int i = 0; i < snake_size; i++) {
-      pair p = pos[i];
-      pixels[p.x][p.y] = LOW; // TURN ON PIXELS OF SNAKE
-    }
-    if(fruit) 
-      pixels[fruitPos.x][fruitPos.y] = LOW;
-  }
-  pair snake_head() {
-    return pos[0];
-  }
-  void generate_fruit() {
-    if(!fruit) {
-      fruit = true;
-      fruitPos.x = random(7);
-      fruitPos.y = random(7);
-    }
-  }
-  void next_move() {
-    for (int i = snake_size; i > 0; i--) {
-      pos[i] = pos[i - 1];
-    }
-    pos[0] = get_next_move(pos[0]);
-    if (fruit) {
-      if (pos[0].x == fruitPos.x && pos[0].y == fruitPos.y) {
-        grow();
-        fruit = false;
-      }
-    }
-  }
-  bool eats_itself() {
-    for(int i = 1; i < snake_size; i++)
-      if( pos[0].x == pos[i].x && pos[0].y == pos[i].y ) return true;
-    return false;
-  }
+ public:
+        Snake() {
+                this->state = 'R';
+                this->snake_size = 4;
+                fruit = false;
+                for (int i = 0; i < snake_size ; ++i) {
+                        pair p;
+                        p.x = 7;
+                        p.y = i;
+                        this->pos[0] = p;
+                }
+        }
+        void change_state(char state) {
+                if (state != 'I') {
+                        // if currently moving up or down and state change is
+                        // left or right, then update
+                        if ((state == 'R' || state == 'L') &&
+                            (this->state == 'U' || this->state == 'D')) {
+                                this->state = state;
+                        }
+                        else if ((state == 'U' || state == 'D') &&
+                                 (this->state == 'R' || this->state == 'L')) {
+                                this->state = state;
+                        }
+                }
+                //else ignore
+        }
+        void snake_to_matrix(int (*pixels)[BOARD_LENGTH]) {
+                for (int i = 0; i < BOARD_LENGTH; ++i) {
+                        for (int j = 0; j < BOARD_LENGTH; ++j) {
+                                pixels[i][j] = LOW;     // CLEAR ALL PIXELS;
+                        }
+                }
+                for (int i = 0; i < snake_size; ++i) {
+                        pair p = pos[i];
+                        pixels[p.x][p.y] = HIGH;        // TURN ON PIXELS OF SNAKE
+                }
+                if (fruit) {
+                        pixels[fruit_pos.x][fruit_pos.y] = HIGH;
+                }
+        }
+        pair snake_head() {
+                return pos[0];
+        }
+        void generate_fruit() {
+                if (!fruit) {
+                        fruit = true;
+                        // random inclusive (starts at 0)
+                        fruit_pos.x = random(7);
+                        fruit_pos.y = random(7);
+                }
+        }
+        void grow();
+        void next_move() {
+                for (int i = snake_size; i > 0; --i) {
+                        pos[i] = pos[i - 1];
+                }
+                pos[0] = get_next_move(pos[0]);
+                if (fruit) {
+                        if (pos[0].x == fruit_pos.x && pos[0].y == fruit_pos.y) {
+                                grow();
+                                fruit = false;
+                        }
+                }
+        }
+        bool eats_itself() {
+                for (int i = 1; i < snake_size; ++i) {
+                        if (pos[0].x == pos[i].x && pos[0].y == pos[i].y) {
+                                return true;
+                        }
+                }
+                return false;
+        }
 };
 
-pair Snake::get_next_move(pair p) {
-  pair r(p);
-  switch (state) {
-  case 'U':
-    r.x = (p.x + BOARD_LENGTH - 1) % BOARD_LENGTH;
-    r.y = p.y;
-    break;
-  case 'D':
-    r.x = (p.x + 1) % BOARD_LENGTH;
-    r.y = p.y;
-    break;
-  case 'L':
-    r.x = p.x;
-    r.y = (p.y + 1) % BOARD_LENGTH;
-    break;
-  case 'R':
-    r.x = p.x;
-    r.y = (p.y + BOARD_LENGTH - 1) % BOARD_LENGTH;
-    break;
-  }
-  return r;
+pair Snake::get_next_move(pair p)
+{
+        pair r(p);
+        switch (state) {
+        case 'U':
+                r.x = (p.x + BOARD_LENGTH - 1) % BOARD_LENGTH;
+                r.y = p.y;
+                break;
+        case 'D':
+                r.x = (p.x + 1) % BOARD_LENGTH;
+                r.y = p.y;
+                break;
+        case 'R':
+                r.x = p.x;
+                r.y = (p.y + 1) % BOARD_LENGTH;
+                break;
+        case 'L':
+                r.x = p.x;
+                r.y = (p.y + BOARD_LENGTH - 1) % BOARD_LENGTH;
+                break;
+        }
+        return r;
 }
 
-void Snake::grow() { 
-  if (snake_size < SNAKE_MAX_SIZE) {
-    pos[snake_size] = pos[snake_size - 1];
-    ++snake_size;
-  }
+void Snake::grow()
+{
+        if (snake_size < SNAKE_MAX_SIZE) {
+                pos[snake_size] = pos[snake_size - 1];
+                ++snake_size;
+        }
 }
 
-const int row[8] = {2, 7, 19, 5, 13, 18, 12, 16};
-
-// 2-dimensional array of column pin numbers:
-const int col[8] = {6, 11, 10, 3, 17, 4, 8, 9};
+const int row[8] = { 2, 7, 19, 5, 13, 18, 12, 16 };
+const int col[8] = { 6, 11, 10, 3, 17, 4, 8, 9 };
 
 // 2-dimensional array of pixels:
 int pixels[8][8];
@@ -122,109 +133,133 @@ int x = 5;
 int y = 5;
 Snake snake;
 
-void setup() {
-  Serial.begin(9600);          // 9600 bps
-  // initialize the I/O pins as outputs
-  // iterate over the pins:
-  for (int thisPin = 0; thisPin < 8; thisPin++) {
-    // initialize the output pins:
-    pinMode(col[thisPin], OUTPUT);
-    pinMode(row[thisPin], OUTPUT);
-    // take the col pins (i.e. the cathodes) high to ensure that
-    // the LEDS are off:
-    digitalWrite(col[thisPin], HIGH);
-  }
 
-  // initialize the pixel matrix:
-  for (int x = 0; x < 8; x++) {
-    for (int y = 0; y < 8; y++) {
-      pixels[x][y] = HIGH;
-    }
-  }
-  randomSeed(analogRead(0));
+// A BIG SAD CROSS
+int dead[8][8] = { 
+        {HIGH, LOW, LOW, LOW, LOW, LOW, LOW, HIGH},
+        {LOW, HIGH, LOW, LOW, LOW, LOW, HIGH, LOW},
+        {LOW, LOW, HIGH, LOW, LOW, HIGH, LOW, LOW},
+        {LOW, LOW, LOW, HIGH, HIGH, LOW, LOW, LOW},
+        {LOW, LOW, LOW, HIGH, HIGH, LOW, LOW, LOW},
+        {LOW, LOW, HIGH, LOW, LOW, HIGH, LOW, LOW},
+        {LOW, HIGH, LOW, LOW, LOW, LOW, HIGH, LOW},
+        {HIGH, LOW, LOW, LOW, LOW, LOW, LOW, HIGH},
+};
+
+/**
+ * The setup routine runs once when you press reset.
+ */
+void setup()
+{
+        Serial.begin(9600); // 9600 bps
+        // initialize the I/O pins as outputs
+        // iterate over the pins:
+        for (int this_pin = 0; this_pin < 8; ++this_pin) {
+                // initialize the output pins:
+                pinMode(col[this_pin], OUTPUT);
+                pinMode(row[this_pin], OUTPUT);
+                // take the col pins (i.e. the cathodes) high to ensure that
+                // the LEDS are off:
+                digitalWrite(col[this_pin], HIGH);
+        }
+
+        // initialize the pixel matrix:
+        for (int x = 0; x < 8; ++x) {
+                for (int y = 0; y < 8; ++y) {
+                        pixels[x][y] = HIGH;
+                }
+        }
+        randomSeed(analogRead(0));
 }
 
-void loop() {
-  if(random(20) == 0) snake.generate_fruit();
-  snake.snake_to_matrix(pixels);
-  snake.next_move();
-  // draw the screen:
-  if(snake.eats_itself()){
-    for(int i = 0; i < 3; i++){
-      for(int j = 0; j < 100; j++)
-        Display();
-     delay(500);
-    }
-    int dead[8][8] = {
-      {0,1,1,1,1,1,1,0},
-      {1,0,1,1,1,1,0,1},
-      {1,1,0,1,1,0,1,1},
-      {1,1,1,0,0,1,1,1},
-      {1,1,1,0,0,1,1,1},
-      {1,1,0,1,1,0,1,1},
-      {1,0,1,1,1,1,0,1},
-      {0,1,1,1,1,1,1,0},
-    };
-    for(int i = 0; i < 8; i++)
-      for(int j = 0; j < 8; j++)
-        pixels[i][j] = dead[i][j];
-    while(true) Display();
-  }
-  for(int i = 0; i < 30; i++) {
-    Display();
-    snake.change_state(read_sensors());
-  }
-  
+/**
+ * The loop routine runs over and over again forever.
+ */
+void loop()
+{
+        snake.generate_fruit();
+        snake.next_move();
+        snake.snake_to_matrix(pixels);
+        for (int i = 0; i < 30; ++i) {
+                display_pixels();
+                snake.change_state(read_sensors());
+        }
+        // draw the screen:
+        if (snake.eats_itself()) {
+                for (int i = 0; i < 3; i++) {
+                        for (int j = 0; j < 100; ++j) {
+                                display_pixels();
+                        }
+                        delay(500);
+                }
+                for (int i = 0; i < 8; ++i) {
+                        for (int j = 0; j < 8; ++j) {
+                                pixels[i][j] = dead[i][j];
+                        }
+                }
+                while (true) {
+                        display_pixels();
+                }
+        }
 }
 
-void readSensors() {
-  // turn off the last position:
-  pixels[x][y] = HIGH;
-  // read the sensors for X and Y values:
-  x = 7 - map(analogRead(A0), 0, 1022, 0, 7);
-  y = map(analogRead(A1), 0, 1022, 0, 7);
-  // set the new pixel position low so that the LED will turn on
-  // in the next screen refresh:
-  pixels[x][y] = LOW;
+/**
+ * Prints the pixels array in the matrix
+ */
+void display_pixels()
+{
+        for (int c = 0; c < 8; ++c) {
+                digitalWrite(col[c], LOW);
+                for (int r = 0; r < 8; ++r) {
+                        digitalWrite(row[r], pixels[r][c]);
+                }
+                delay(1);
+                display_clear();
+        }
 }
 
-void Display()    
-{  
-  for(int c = 0; c<8;c++)  
-  {  
-    digitalWrite(col[c],LOW);//use thr column 
-    //loop
-    for(int r = 0;r<8;r++)  
-    {  
-      digitalWrite(row[r],(pixels[r][c]+1)%2);  
-    }  
-    delay(1);  
-    Clear();  //Remove empty display light
-  }  
-}  
-  
-void Clear()                          //清空显示  
-{  
-  for(int i = 0;i<8;i++)  
-  {  
-    digitalWrite(row[i],LOW);  
-    digitalWrite(col[i],HIGH);  
-  }  
-} 
-
-char read_sensors() {
-  //int clicked = digitalRead(z); // if 0, then clicked
-  //if(!clicked) return 'C';
-  x = map(analogRead(A0),0,1023,0,10) - 5;
-  y = map(analogRead(A1),0,1023,0,10) - 5;
-  if(abs(x) <= 1 && abs(y) <= 1) { // test if joystick is the middle with some leeway
-    return '\0';
-  }else if(abs(x) > abs(y) ) { // test if move in x axis is > than in y axis
-    if(x > 1) return 'L';
-    else return 'R';
-  } else {
-    if(y > 1) return 'U';
-    else return 'D';
-  }
-  return '\0';
+/**
+ * Remove empty display light
+ * 清空显示
+ */
+void display_clear()
+{
+        for (int i = 0; i < 8; ++i) {
+                digitalWrite(row[i], LOW);
+                digitalWrite(col[i], HIGH);
+        }
+}
+
+/**
+ * Returns the current joystick input with some leeway
+ * I means Iddle
+ * L means Left
+ * R means Right
+ * U means Up
+ * D means Down
+ */
+char read_sensors()
+{
+        //int clicked = digitalRead(z); // if 0, then clicked
+        //if(!clicked) return 'C';
+        x = map(analogRead(A0), 0, 1023, 0, 10) - 5;
+        y = map(analogRead(A1), 0, 1023, 0, 10) - 5;
+        // test if joystick is the middle with some leeway
+        if (abs(x) <= 3 && abs(y) <= 3) {
+                return 'I';
+        // test if move in x axis is > than in y axis
+        } else if (abs(x) > abs(y)) {
+                if (x > 1) {
+                        return 'R';
+                } else {
+                        return 'L';
+                }
+        } else {
+                if (y > 1) {
+                        return 'U';
+                } else {
+                        return 'D';
+                }
+        }
+        return 'I';
 }