Fruit Machine Chat

I know that the bonus appears at random. But I was wondering if anyone knows how it determines what type of bonus you get when it does appear (ie letter tips, extra lives etc).

It has a sort of traffic light system and what you get seems to depend on your timing when pressing the Hex button.

Does anyine know how the "secret help" Hex icon in the bottom right hand corner works? Most of the time it gives you free letters but I have seen it add lost lives. Would be great to work out how to do this at will!