| http://www.w3.org/ns/prov#value | - Whereas the conventional track or roadway is made of rigid plastic or metal which is preshaped and has a substantially flat bottom surface, the trackway section 20 of FIG. 9 is preferably made of a flexible plastic material such as polyethylene, polyvinyl chloride, acetate or other polymers which, in the thin cross section illustrated or modifications thereof, is sufiiciently flexible so as to pe
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