| 摘要 |
<p>The concrete pillar is for the revetment of slopes etc, being of regular hexagonal shape. Along all its ribs are recesses extending for its full height. Its top surface (21) is of flat square shape, joining onto faces sloping downwards (23-26) on all sides. The bottom of each recess can be formed by two flat faces (13, 14) at an obtuse angle to each other.</p> |
