gill had a pufferfish alter....he might like to look at 'this one':

https://www.youtube.com/watch?v=hpdlQae5wP8

explained in more detail - in the video below:

https://www.youtube.com/watch?x-yt-cl=84924572&v=TTg0xHzPrQI&feature=player_detailpage&x-yt-ts=1422411861