Interlocking panel structure

Claim 1

A STRUCTURE FORMED OF A PLURALITY OF ELONGATED PANEL FORMING UNITS EACH COMPRISING SUBSTANTIALLY PARALLEL SPACED APART WALLS AND A TRANSVERSE WEB BETWEEN THEM, CURVED TONGUE AND GROOVE ELEMENTS ON OPPOSITE LONGITUDINAL MARGINAL PORTIONS RESPECTIVELY OF ONE WALL AND ARRANGED TO PIVOTALLY INTERENGAGE WITH CORRESPONDING CURVED GROOVE AND TONGUE ELEMENTS ON JUXTAPOSED UNITS UPON RELATIVE ROTATION OF THE UNITS ABOUT THEIR INTERENGAGED TONGUE AND GROOVE ELEMENTS, REVERSELY FACING STRAIGHT SIDED HOOK-LIKE ELEMENTS ON OPPOSITE MARGINAL PORTIONS RESPECTIVELY OF THE OTHER WALL EXTENDING AT ANGLES NOT EXCEEDING 90* TO THE EXTERIOR FACE OF SAID OTHER WALL AND ARRANGED TO POSITIVELY INTERENGAGE CORRESPONDING HOOKLIKE ELEMENTS ON JUXTAPOSED UNITS UPON SAID RELATIVE ROTATION OF THE UNITS TO INTERLOCK THE UNITS TO EACH OTHER WITH THEIR WALLS IN COMMON PLANES, ONE OF THE HOOK-LIKE ELEMENTS BEING ON THE OUTER FACE OF THE UNIT WALL FROM WHICH IT PROJECTS AND THE OTHER WALL, THERE BEING A WIDE ON THE INNER FACE OF SAID UNIT WALL, THERE BEING A WIDE RECESS BETWEEN SAID HOOK-LIKE ELEMENTS PROVIDING CLEARANCE BETWEEN THE INTERENGAGED HOOK-LIKE ELEMENTS TO RECEIVE AN EDGED TOOL FOR PRYING THE INTERLOCKED HOOK-LIKE ELEMENTS APART.