procedure main(arglist)
every s := genbs(!arglist) do
   write(image(s), if isbalanced(s) then " is balanced." else " is unbalanced")
end

procedure isbalanced(s) # test if a string is balanced re: []
return (s || " ") ? (bal(,'[',']') = *s+1)
end

procedure genbs(i)  # generate strings of i pairs of []
s := ""
every 1 to i do s ||:= "[]"       # generate i pairs
every !s := ?s                    # shuffle
return s
end