To mirror a drawn object in Surfer:

1. Select the object.
   
2. Click Home | Selection | Transform.
3. In the Transform dialog, if you want to mirror x, set the X Scale to -1. If you want to mirror y, set the Y Scale to -1. 
   
4. Click OK.
   

If you would like to add your vote to our suggestion file for a "mirror x" or "mirror y" command, please email surfersupport@goldensoftware.com. 

Updated October 25, 2018