| 摘要 |
<p>An extrusion (10) including a central wall portion (12) and a surrounding perimeter portion (14, 18) whereby the central wall portion (12) divides the extrusion (10) into opposing chambers, said perimeter portion (14, 18) having a respective opening therein into each of said chambers and each said chamber being able to have a perimeter portion (14, 18) of a further extrusion (10) locked thereinto to form an interlocked unit.</p> |
