// The camera lifts up while looking at the same point
void setup() {
  size(400, 400, P3D);
  fill(204);
}

void draw() {
  lights();
  background(0);
  // Change height of the camera with mouseY
  camera(30.0, mouseY, 220.0, // eyeX, eyeY, eyeZ
         0.0, 0.0, 0.0, // centerX, centerY, centerZ
         0.0, 1.0, 0.0); // upX, upY, upZ
  noStroke();
  box(90);
  stroke(255);
  line(-100, 0, 0, 100, 0, 0);
  line(0, -100, 0, 0, 100, 0);
  line(0, 0, -100, 0, 0, 100);
}