Flipping a Shape
A flip is a reflection across a vertical or horizontal line that intersects the center of the bounding box. The optional @flipH and @flipV attributes control horizontal and vertical flipping, respectively. Each is absent or equal to 0 if no flipping is to be performed, and equal to 1 if flipping is to be performed.

The following XML fragment illustrates a shape that has been flipped both horizontally and vertically.
<a:xfrm flipH="1" flipV="1"> <a:off x="3964937" y="2652643"/> <a:ext cx="168838" cy="1219199"/> </a:xfrm>