Yes that is called the classic shell game or find the Lady street corner card game , just trade the DD that is in front of you and never add to a loosing position , if you do , your a MORON , and I do not care for folks who tell people to buy when they do not hold a Series 27 license to do so .
The Series 27 exam is administered by the Financial Industry Regulatory Authority (FINRA) and covers seven general topics, including: Customer Protection, Federal reserve Board Regulations, Net capital Requirements and Uniform Practice Rules.