Various embodiments of variable length piston and connecting rod assemblies for imparting a variable compression ratio to an internal combustion engine. This invention also provides for the moment applicable on the cap has a different strength that the moment applicable on the base. Associated to the rigid body of the closing member there are at least partially elastic or yielding complements, which are functionally distinct from the sealing means and are able to undergo deformation in the course of the use of the closing member. A data shape allows users to declaratively specify a set of policies to be applied to all queries associated with the data shape. A distance between the two lenses falls within a range from 0.