Exhibit: Spinning Picture

The picture is spinning at a rate of about 10 turns per second, so it is totally blurred.

When you press the button, you operate a photo flash gun which lights up the
picture when it is the right way up, and you see a sharp picture.

The flash lasts for less than a thousandth of a second, so 
the picture only turns by about one degree whilst it is lit up, but you see the picture for a lot longer than this, because the chemical changes produced by the bright light in the receptor cells at the back of our eyes take a long time to die away.