begin

;
; Create some dummy data for the surface plot.
;
  N  = 41
  PI = 3.14159

  x = fspan(0.,N-1,N)
  y = fspan(0.,N-1,N)
  z = 3.*sin(onedtond((PI/5) * ispan(0,N-1,1),(/N,N/)))
;
; Create an X workstation.
;
  wid = create "wks" xWorkstationClass defaultapp end create

;
; Retrieve the GKS workstation id, which is necessary in order to
; interact with low-level libraries.
;
  getvalues wid
    "wkGksWorkId" : gkswid
  end getvalues

;
; Call tdez2d to draw a surface plot.
;
  rho   =   3.0
  theta = -45.0
  phi   =  55.0

  tdez2d(gkswid, x, y, z, rho, theta, phi, 6)

  frame(wid) ; Advance the frame.
end