They make what is called Shade sails. They are a heavy duty nylon or
polyproplyene fabric made in the shape of a triangle. They are
supported by using three poles and three stakes in the ground or tied
off to other existing structures and tensioned. The triangle shape,
and outer perimeter cable they have works better in windy condiitons
than a square shape does as it allows any captive air under it to
bleed off quick and not create as much lift and billow up as a square
would. A lot of ponders on another forum speak very highly of them in
giving them the needed shade for their ponds.
A ready made 12 x 12 x 12 foot triangle shade sail is about
$130......and all you need is a means to support it, usuing pipes
wood posts or other structure.

http://www.shadesails.com/newpage11.htm

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Put some color in your cheeks...garden naked!
"The original frugal ponder"
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