a bedding foundation having a nestably stackable spring assembly , including a border wire having a generally rectangular cross - section . the foundation &# 39 ; s spring assembly may be nestably stacked with numerous other such assemblies for transportation , thereby avoiding the need to compress and tie the assembly for shipping . each foundation assembly includes a number of corrugated support wires having alternating peaks and valleys . the border wire is generally rectangular in cross - section to reduce wire costs without compromising beam strength of the border wire .