```python
def setup():
global c
py5.size(640, 360, py5.P2D)
c = py5.create_shape(py5.RECT, -20, -20, 40, 40)
c.set_stroke("#FFFFFF")
def draw():
py5.background(51)
c.set_fill(py5.color(py5.random_int(255)))
py5.translate(py5.mouse_x, py5.mouse_y)
py5.shape(c)
```