Posted by Neil Wyatt on 07/05/2015 18:12:26:
Interesting idea Clive. would work for a semi-permanent position in the garden. …
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Agreed, a ground anchor and tension wire is an excellent alterntive to gravity, and avoids carrying all those heavy rocks and sandbags around. 
As an engineer … you might find inspiration here … It's a lovely piece of work, and could easily be scaled-up.
MichaelG.