double :: Int -> Int
-- testing 4 combinations of argument values
-- pruning with 14/25 rules
-- looking through 3 candidates of size 1
-- looking through 4 candidates of size 2
-- looking through 9 candidates of size 3
double x  =  x + x

add :: Int -> Int -> Int
-- testing 4 combinations of argument values
-- pruning with 14/25 rules
-- looking through 4 candidates of size 1
-- looking through 18 candidates of size 2
-- looking through 101 candidates of size 3
add x y  =  x + y

square :: Int -> Int
-- testing 3 combinations of argument values
-- pruning with 14/25 rules
-- looking through 3 candidates of size 1
-- looking through 4 candidates of size 2
-- looking through 9 candidates of size 3
square x  =  x * x

tnpo :: Int -> Int
-- testing 3 combinations of argument values
-- pruning with 14/25 rules
-- looking through 3 candidates of size 1
-- looking through 4 candidates of size 2
-- looking through 9 candidates of size 3
-- looking through 23 candidates of size 4
-- looking through 26 candidates of size 5
-- looking through 65 candidates of size 6
-- looking through 75 candidates of size 7
tnpo x  =  x + (x + (x + 1))