3d with inner rotation

inner_rotation_3d.pde

float z;
float r = 0;

void setup()
{
  size(500, 500, P3D);
  z = 0;
}

void draw()
{
  background(255);
  translate(mouseX, mouseY);

  pushMatrix();
    r++;
    rotateY(radians(r));
    translate(-25, -25);
    rect(-25, -25, 50, 50);
    ellipse(0, 0, 50, 50);
    
    rotateY(radians(90));
    rect(0, 0, 50, 50);
  popMatrix();
}

void mouseMoved() {
  z = map(mouseX, 0, width, 0, 360);
}