Why didn't I think of this before? The structural strength of an object is affected by its shape. Think of an I-beam or a piece of paper folded accordion style. This could be held in place with metal stakes and reinforced with triangular wood braces to keep my dog out. The perimeter has concrete and flagstones around it. This will be far cheaper and easier than portable fencing. (I haven't gotten any further than the one panel I built.)
Do-it-yourself health. Low-carb, mostly evolutionary.