DECLARE SUB peset (x!, y!, z!, c!, c!)
SCREEN 13: FOR i = 0 TO 63: PALETTE i, i: NEXT
FOR z = 100 TO -100 STEP -.65
  FOR x = -100 TO 1 STEP .65
    IF x <> 0 OR z <> 0 THEN
      q = SQR(x * x + z * z) / 5
      p = -SIN(q) / q / 5
      xx = p * x
      zz = p * z
    END IF
    qq = 1.73 * SQR(xx * xx + 1 + zz * zz)
    c1 = (1 + (xx + 1 - zz) / qq) * 30
    c2 = (1 + (-xx + 1 - zz) / qq) * 30
    CALL peset(x, COS(q) * 5, z, c1, c2)
   NEXT
NEXT

SUB peset (x, y, z, c1, c2)
  zz = z / 2
  yy = 100 - y - zz
  xx = 160 + z / 2
  PSET (xx + x, yy), c1
  PSET (xx - x, yy), c2
END SUB