int x=60,
y=80,
w=120,
h=60,
sx=0,
score=0;
float
r_x=random(0,240),
r_y=random(0,240);

void setup(){
  background(0);
  size(240,240);
  textSize(30);
  textAlign(CENTER);
  text ("START",120,120);
 stroke(255); 
  noFill();
rect(60,80,120,60);

}

void draw(){
  float d = dist(mouseX, mouseY,r_x,r_y);
  if((mousePressed == true) && (mouseX > x) && (mouseX < x+w) &&
(mouseY > y) && (mouseY < y+h) && (sx == 0)){
  background(0);
sx++;
}
if(sx == 1){
  stroke(255,0,0);
  fill(255,0,0);
  ellipse(r_x,r_y,20,20);
}

if((sx >= 1) && (d < 20)){
fill(0,255,0);
stroke(0,255,0);
ellipse(r_x,r_y,20,20);
sx++;}

if((sx >= 1) && (mousePressed == true) && (d < 20)){
r_x=random(0,240);
r_y=random(0,240);
background(0);
sx=1;
score++;
}

}