(under the class definition) Structure including a barrier, e.g., wall, which has its opposite faces both curvilinear and substantially parallel or a module specialized to use in forming such a barrier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
80.1, 86+, 192+, 223.3, 236.1, 236.2, 244, 329+, and 639+, for another construction having a curvilinear feature.
503, for a barrier with an internal fluid passage formed by modules.
575, for a module having non-parallel joint faces e.g., keystone shaped block.
606+, for a hollow block which may be used to form a construction with a through passage. SEE OR SEARCH CLASS
138, Pipes and Tubular Conduits, appropriate subclasses, particularly
100+, and 157+, and see the reference to Class 138 in the class definition of this class (52).
