RosettaCodeData/Task/Mutual-recursion/PostScript/mutual-recursion-2.ps

/F {
{
    {0 eq} {pop 1} is?
    {0 gt} {dup 1 sub F M sub} is?
} cond
}.

/M {
{
    {0 eq} {pop 0} is?
    {0 gt} {dup 1 sub M F sub} is?
} cond
}.