摘要 |
A concave-convex structure is composed of a plurality of pole or rod elements including at least two series of rows of such rods, the rods of each row being substantially parallel to one another. The rows are intersecting, but are uniform in respective orientation. The rods are stabilized at the intersections by fittings which permit relative sliding movement of restricted degree. These fittings are secured to a flexible membrane or body portion.
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