nOrder=4
call triangle 1, 1, nOrder
end

SUB triangle x, y, n
    IF n = 0 THEN
        LOCATE x,y: PRINT "*";
    ELSE
        n=n-1
        length=2^n
        call triangle x, y+length, n
        call triangle x+length, y, n
        call triangle x+length*2, y+length, n
    END IF
END SUB