program define symnum
    version 4.0

    preserve
    clear

    set obs 10
    gen x=_n
    gen y=_n

    gph open
    gph pen 2

    graph y x,xlab ylab
    gphconv

    local i=1
    while `i' <=10 {

        drpoint `i' `i' 1000 `i'
        local i=`i'+1}

    gph close

    restore

end
exit