This animation illustrates the desirability of a torsion free response and undesirability of the torsion dominated response during earthquakes. The typical table shown moves back and forth with similar load and demand on all four legs. Once however, a rigid block is inserted between two legs, these legs cannot move as much and as a result the other two legs have to move significantly more. If this excessive demand is not accounted for in design, damage or collapse could occur.