You must be seeing this double mastery thing given by american express with the statue.
If you dont know how to get it.
Here is a pictorial step by step guide to get it.
First click on the icon shown below the farm.
or go to this link if you dont see the icon.
http://www.facebook.com/americanexpress?v=app_154635461249815
When you go to the link or click the icon you go to a new page which looks like this.
Click the like button on it.
And than after that click the button shown by arrow to get the code.
When you click the button it will ask for the permit to access your profile.
Click allow button.
After you click that button you will be provided with the code at the blank space.
One arrow points towards the code you will get.
Now click on the button "click to redeem" as shown by the arrow. After that you will get another tab open.
Now click on the button to connect with the facebook.
That will again ask for permit to access information on your profile.
Press allow button to go to the next step.
Now paste or enter the code that you got in the precious steps in the space provided as pointed by arrow.
After that press redeem now button.
That will take you to the next step.
Now press 'go play farmville' button to get your reward. Also you get the Amex Centurian Statue. in your gift box after this step. Where you need to click on the facebook button.
After you click on the facebook button you are taken to your farm.
There you can find the statue in your gift box.
Now place that statue on the farm.
You will see this screen.
Press continue to enjoy double mastery.