5 rem Generates a 2-tone alarm sound continuously
  10 dim y
  20 dim x, z
  30 dim led as pin pt2 for digital output
  40 let y = 1000
  50 let z = 1
  60 while 1 do
  70   for x = z to y
  80     let led = !led
  90     sleep x us
 100   next
 110   for x = y to z step -1
 120     let led = !led
 130     sleep x us
 140   next
 150 endwhile