embodiments the members may be of different lengths and may be curved or otherwise u2018 non straight u2019 note in the expanded state of fig1 that the nested v shapes are nearly triangular while in the collapsed state of fig2 the members associated with each unit cell assume a more parallel arrangement wherein the sides of the members are proximate to one another if not touching in some cases it is also worth noting that in this and other designs some of the members form substantially parallel lines 150 152 154 156 in the expanded state to provide a structural building element such as a wall component a fabric 104 or other cover may be attached to the v shapes preferably at the joints 102 so as to realize a panel structure that may readily expand and collapse alternatively the fabric material may be bonded to the sides of the various members although only one fabric sheet is depicted in fig1 and 2 a second sheet may be provided on the opposing side thereby creating a trapped air space which may be filled with insulative material s as seen in fig1 in the expanded state the flexible sheet is substantially unfolded whereas in the collapsed states of fig2 the sheet is folded along with the structure itself the members and joint bodies may be made out of any suitable material such as plastics metals or wood the members may be solid or hollow any type of fabric may be used including canvas nylon and so forth in lightweight implementations for shelters tents and the like one preferred combination comprises aluminum interconnecting members aluminum or plastic joint bodies and rip stop nylon fabric fig3 is a more.