processing starter

PImage aUp;  // up arrowPImage aLft;  // left arrowPImage aDwn;  // down arrowPImage aRt;  // right arrow//WHITE VERSIONSPImage aUpW;  // up arrowPImage aLftW;  // left arrowPImage aDwnW;  // down arrowPImage aRtW;  // right arrowint x;int y;PImage Up;PImage Dwn;PImage Lft;PImage Rt;void setup() {  size(600, 600);  delay(120);    //inactive images  aUp = loadImage("images/upArrow.GIF");  aLft = loadImage("images/leftArrow.GIF");  aDwn = loadImage("images/downArrow.GIF");  aRt = loadImage("images/rightArrow.GIF");      //active images  aUpW = loadImage("images/upArrowWhite.GIF");  aLftW = loadImage("images/leftArrowWhite.GIF");  aDwnW = loadImage("images/downArrowWhite.GIF");  aRtW = loadImage("images/rightArrowWhite.GIF");      Up = aUp;  Dwn = aDwn;  Lft = aLft;  Rt = aRt;    x = 0;  y = 0;}void draw(){    //the moving images  if(y<600) {y++;}  background(0);  image(aUp, 0, y, width/4, height/4);  image(aLft, width/4, y, width/4, height/4);  image(aDwn, width/2, y, width/4, height/4);  image(aRt, width-width/4, y, width/4, height/4);     //the Static state images  image(Up, 0, height-height/4, width/4, height/4);  image(Lft, width/4, height-height/4, width/4, height/4);  image(Dwn, width/2, height-height/4, width/4, height/4);  image(Rt, width-width/4, height-height/4, width/4, height/4);}  void keyPressed() {  if(key == CODED){    if (keyCode == UP){      Up = aUpW;    } else if(keyCode == DOWN){      Dwn = aDwnW;    } else if(keyCode == LEFT) {      Lft = aLftW;    } else if(keyCode == RIGHT) {      Rt = aRtW;    } else {      Up = aUp;      Dwn = aDwn;      Lft = aLft;      Rt = aRt;    }  }}void keyReleased() {  if(key == CODED){    if (keyCode == UP){      Up = aUp;    } else if(keyCode == DOWN){      Dwn = aDwn;    } else if(keyCode == LEFT) {      Lft = aLft;    } else if(keyCode == RIGHT) {      Rt = aRt;    } else {      Up = aUp;      Dwn = aDwn;      Lft = aLft;      Rt = aRt;    }  }}