Hi all!
this is my first post, so heres what happening:
I have a final project where i have to create a game for processing, and my idea was a circle avoiding obstacles controlled by the mouse, this is what i did so far:

float z = 100;
float speed = 5;

float circleX, circleY;
float circleRadius = 20;
 
float rectX = 600;
float rectY = int(random(0,250));
float rectWidth = 10;
float rectHeight = 50;
 
void setup() {
  size(600, 300);
  ellipseMode(RADIUS);
  smooth();
}
 
void draw() {
  background(204);
 
 z -= speed;
 rectX = 600+z;
 if(rectX < 0) {
  rectX = -100;
 }
 
  circleX = mouseX;
  circleY = mouseY;
 
  if (rectCircleIntersect(rectX, rectY, rectWidth, rectHeight, circleX, circleY, circleRadius) == true) {
    fill(0);
  }
  else {
    fill(255);
  }
 
  rect(rectX, rectY, rectWidth, rectHeight);
  ellipse(circleX, circleY, circleRadius, circleRadius);
 
}
 
boolean rectCircleIntersect(float rx, float ry, float rw, float rh, float cx, float cy, float cr) {
 
  float circleDistanceX = abs(cx - rx - rw/2);
  float circleDistanceY = abs(cy - ry - rh/2);
 
  if (circleDistanceX > (rw/2 + cr)) { return false; }
  if (circleDistanceY > (rh/2 + cr)) { return false; }
  if (circleDistanceX <= rw/2) { return true; }
  if (circleDistanceY <= rh/2) { return true; }
 
  float cornerDistance = pow(circleDistanceX - rw/2, 2) + pow(circleDistanceY - rh/2, 2);
  return cornerDistance <= pow(cr, 2);
 
}

but im blocked now, this is REALLY hard, you see where is

 z -= speed;
 rectX = 600+z;
 if(rectX < 0) {
  rectX = -100;
 }

i cant make that the rectangle appears again on the right, and i dont know how to create a gameover screen, a intro screen, nothing, can anybody help me? i dont have much time, and im trying for ages but im not used to Processing, you can improve if you want.

WoRmTa1L