void setup() {
  size(500,500);
  background(0);
  smooth();
}

void draw() {
  float x = mouseX;
  float y = mouseY;
  float m = second();
  fill(255);
  stroke(0);
  Brushy (x, y, m);
}

void Brushy (float x, float y, float m) {
  ellipse(x, y, m*3, m*3);
}