antialias 1
set rseed <time 4>

number randoma
{
   set bb 198621
   set mm (98621+<time 4>)
   set bl (rseed*bb+1)
   set rseed (bl%mm)
   value (rseed%100)
}

paper 0
pen 100

set pold 50
set max 50
set amp 40

repeat n 1 max
{
   set pnew ((<randoma>%amp)-amp+90)
   line ((n-1)*100/max) pold (n*100/max) pnew
   set pold  pnew
}