I would like to be able to print mirror images of geometric shapes.
Choose File > Print. If the Print dialog sheet is not expanded, click the disclosure triangle. In the application pop-up menu, choose Layout. Click the Flip Horizontally check box. Print.
This will work in all apps which support the standard Mac OS X print dialog, including Adobe Reader, although the print dialog sheet may look slightly different.
For more information on printing, see
Mac 101: Printing (Mac OS X v10.6)
If you don't know how to open a document with an application other than the default, then you're new to Mac OS X. Read
Mac 101: Mac essentials
If you're coming from Windows, read
Switch 101: On Windows, I used to...
What’s it called on my Mac?