fence module of fig1 in the illustrated embodiment each base frame 21 includes three parallel longitudinal beams 40 41 42 and five parallel lateral beams 43 44 45 46 47 two of the longitudinal beams serve as a front beam 40 and as a rear beam 42 of the base frame two of the lateral beams serve as end beams 43 47 as discussed with reference to fig1 and 2 the first upright posts 22 and the extension arms 23 are coupled to the front beam 40 of the base frame in one embodiment these connection points proximate to the connection points 52 53 coupling the end lateral beam 43 and the central lateral beam 45 to the front beam 40 in the illustrated embodiment no support section elements are coupled to one of the two end beams 47 to provide a continuous perimeter fence adjacent base frames are initially joined by connecting an end beam 47 which does not include supporting structure to an end beam 43 on an adjacent module which includes supporting structure as may be appreciated in some embodiments the base from is coupled to other base frames before any supporting structure is installed in some embodiments the base frame 21 is anchored to the underlying substrate by anchor elements not shown positioned adjacent to beams of the base frame accordingly the optional anchoring elements are placed.