```python
def setup():
py5.size(200, 200)
py5.rect_mode(py5.CENTER)
def draw():
py5.square(py5.random(py5.width), py5.random(py5.height), 10)
def mouse_clicked(e):
if e.is_shift_down():
py5.println('the shift key is down')
else:
py5.println('the shift key is not down')
```