Figure 1444 shows electron diffraction patterns of the Al₆₄Cu₂₂Co₁₄ DQC (decagonal quasicrystal, see page1453) taken with the incident beam parallel to three primary axes. The diffraction patterns taken along directions q and p indicate that the structure includes two layers along the ten-fold axis and thus has centrosymmetry. The reflections marked by the arrows in Figure 1444 (c) disappear due to the existence of a 10₅ screw axis in the space group of P10₅/mmc.