/*
s([heads(C)],P).
C = coin
P = 0.51 ?;
no
s([tails(C)],P).
C = coin
P = 0.49 ?;
no


*/

heads(Coin): 1/2; tails(Coin) : 1/2:-toss(Coin),\+biased(Coin).
heads(Coin): 0.6 ; tails(Coin) : 0.4:-toss(Coin),biased(Coin).
fair(Coin):0.9 ; biased(Coin):0.1.
toss(coin).
