Shapes can be flipped both horizontally and vertically, as well as rotated. Flipping and rotation are specified with attributes on the <a:xfrm> element, which is a child element of <p:spPr> (shape properties) element. A shape is flipped horizontally with the flipH attribute, and it is flipped vertically with the flipV attribute. Both are booleans, with a value of true indicating that the shape should be flipped. Roation is specified with the rot attribute. Values are in 60,000ths of a degree, with positive angles moving clockwise or towards the positive y-axis.
Here is the shape without vertical flipping.
Here is the shape with vertical flipping.
Below is the same shape as above (without the vertical flipping), now rotated 45 degrees.