Now we can also use a Punnett square to basically calculate what the result is. So in trial number one in the first event we can either get heads or we can get tails. So let's use I guess red for heads or actually let's use red for event number one and let's use blue for event number two. Okay, so this is event number one first trial, event number two second trial. Now what's the probability of it being hence? Well it's basically one half.