A postage stamp design error is a mistake made during the design phase of the postage stamp production process. Design errors most commonly occur as minor mistakes, such as a missing letter in the binomial name of an organism depicted on the stamp, but some have been major gaffes, such as a map appearing to lay claim to another country's territory, or the depiction of the wrong person on the stamp. A design error caught during the production process may disappear quietly, with copies of the error only getting into the public's hands via unscrupulous employees (these are therefore not considered "real" stamps). Design errors are often caught during the distribution process, when large numbers of postal workers are scrutinizing the new stamp; although officials may elect to withdraw all the stamps at that point, it is very difficult to retrieve every one of them, and in these instances a few may end up being sold and used. The exact circumstance are important, because once the stamp is sold to a customer, whether or not against the postal service's rules, it is considered to be legitimate. The Legends of the West sheet was a particularly difficult case. Shortly before the release of this commemorative series (and after sheets had already been sent to post offices and found their way into collectors' hands), a claim was made that the image of Bill Pickett used for his stamp's painting was actually an image of his brother Ben. The United States Postal Service decided to recall the stamps and re-issue them later with Pickett's stamp based on an image known with certainty to be him. The USPS sold the entire run of erroneous stamps at face value by lottery. Somewhat rarer is a design error that is first noticed by a member of the public. This usually happens within a few days of the stamp first going on sale, and usually ends up as the subject of newspaper articles. A recent example of this is the Maya Angelou stamp issued by the U.S. Postal Service on April 7, 2015. The stamp contains a quotation that had been frequently attributed to Ms. Angelou, but was really written by Joan Walsh Anglund. In this circumstance, the Postal Service was unaware of the real author until it was brought to their attention by The Washington Post. The response of postal officials may include withdrawal of all