int ballPositionX = 250;
int ballPositionY = 250;
int ballSize = 20;
int slowerSpeed = 50;
int mouvement = 250;
int linePt1 = 100;
int linePt2 = 250;
int linePt3 = 400;
int rightLimit, leftLimit, bottomLimit, topLimit;

int moveX, moveY;

void setup(){
  size(500,500);
}

void draw(){
  background(255);
  line(linePt1,linePt2,linePt3,linePt2);
  line(linePt2,linePt1,linePt2,linePt3);
  ellipse(ballPositionX, ballPositionY, ballSize, ballSize);
  moveX = (mouseX - 250);
  moveY = (mouseY - 250);
  ballPositionX = min(ballPositionX, moveX+ballPositionY);
  ballPositionY = max(ballPositionY, moveY+ballPositionX);
}