void setup() {
   size(640,480);  //Set the size of the screen 
   smooth(); fill(255); stroke(255);
   rectMode(CENTER); textAlign(CENTER, CENTER); 
};
void draw() {
  fill(0); textSize(70);
   if (mouseX<4) {
   background(170, 10, 0); 
   text("Let's\nstart walking!", width/2, height/2, width, height); 
  }
  else if (mouseX>635) {
   background(10, 170, 0); 
   text("Hurray!\nLevel Completed", width/2, height/2, width, height);
  }
  else {
   background(10, 10, 10); 
   fill(100, mouseX * (255.0/800), 0);
   arc(width/2, height/2, 370, 370, 0, pmouseX/100.0);
   fill(0);
   arc(width/2, height/2, 170, 170, 0, pmouseX/100.0);
   stroke(0); fill(255); textSize(37);
   text("steps:\n" + mouseX, width/2, height/2, width, height);
  }
};