int redAmount=50, blueAmount=50, greenAmount=50;
color circleColor;

void setup(){
  size(255,255);
  frameRate(30);
}

void draw(){
  background(redAmount, blueAmount, greenAmount);
  redAmount=mouseX;
  blueAmount=mouseY;
  greenAmount=(mouseX-mouseY);
  drawRects();
  drawCircle();
  if (mousePressed){
    frameRate(mouseX);
  }
}
void drawCircle(){
  circleColor=color(255-redAmount, 255-blueAmount, 255-greenAmount);
  fill(circleColor);
  ellipse(100,100,50,50);
}

void drawRects(){ // this can be a method that you write on your own!
  for (int i=0; i<mouseX/10; i++){
    rect(random(0,255), random(0,255), 10, 10);
  }
}