ntim = 5
  nlat = 10
  nlon = 20

  x   = random_uniform(-100,100,(/ntim,nlat,nlon/))
  x!0 = "time"
  x!1 = "lat"
  x!2 = "lon"

  y   = random_uniform(0,1000,(/ntim,nlat,nlon/))
  y!0 = "time"
  y!1 = "lat"
  y!2 = "lon"

;--Note what happens in "test.nc" when you don't name the dimensions
  z   = random_uniform(0,1000,(/ntim,nlat,nlon/))

  fout_name = "test.nc"
  system("rm " + fout_name)
  fout = addfile(fout_name,"c")
  fout->x = x
  fout->y = y
  fout->z = z