aUCBLogo Demos and Tests / primes

to primes [size 8192] [flags array size]
   t=timefine
   imax=int sqrt size
   for [i 2 imax 1] ~
   [   if flags.i==[] ~
      [   for [k i+i size i] ~
         [   flags.k=false
         ]
      ]
   ]
   pr timefine-t
   repeat size [if empty? flags.repcount [(type repcount " )]]
   (pr)
end