( http://c...content-available-to-author-only...e.com/questions/48476/programming-languages-through-the-years )

: year ." Forth was made in 1970!" ;

: printn 
    dup 2 > if
        dup 0 do 
            ." N" dup 1- 1 do 
                I J = if ." N" 
                else space 
                then 
            loop 
            ." N" cr 
        loop 
    else 
        dup 2 = if ." NN" cr ." NN" cr 
        else ." N" cr 
        then
    then
    drop ;

: gcd begin ?dup while swap over mod repeat ;

year cr cr 
5 printn cr
18 12 gcd .