Patent ID: 7340868

Claim:
A universal structural element ( 1 ) comprising: (a) a body having a plurality of longitudinal sides and at least two end sides ( 3 ); (b) an undercut longitudinal groove ( 2 ) on at least one longitudinal side, each said undercut longitudinal groove ( 2 ) extending from a first end side ( 3 ) to a second end side ( 3 ); (c) intersecting undercut grooves ( 4 ) in at least one of said at least two end sides ( 3 ), said intersecting undercut grooves ( 4 ) extending between longitudinal sides ( 2 ); (d) said undercut longitudinal grooves ( 2 ) and said intersecting undercut grooves ( 4 ) having substantially consistent cross-sections; and (e) said intersecting undercut grooves ( 4 ) connected to said undercut longitudinal grooves ( 2 ).