Fu Yin(伏吟)
Fu Yin chart is when stem are the same or double. A Pure Fu Yin is when the Star and Door are back in their original position. So what does it mean in destiny reading as compare to forecasting vs strategic execution?
Fu Yin in forecasting generally indicates that progress will be slow and that supported actions will be limited, these affects will still, however, be couched within the reading dictated by the stems. Among the Ten Stems, there are Three Nobles and Six Crescents. The Nobles of Yi 乙, Bing 丙, and Ding 丁 as well as the stem of Wu 戊 are thought to be auspicious and, as such, when a Fu Yin formation falls on one of these stems, the impact will be to slow the progress of otherwise positive events.
When Fu Yin falls on one of the remaining stems, the effect may be to cause complete stagnation or, indeed, to slow the development of more negative events. The final judgment over the specific impact of Fu Yin will need, however, to take into consideration the overall combinations of the Stars, Doors and Deities in that particular Palace, as well as the relationships between the Five Elements and the other Palaces.
While in Destiny Reading, it is actually denote as Pure Energy that we like to see. We can see that what you appear within inside and outside is identical, your thoughts and actions are align. People will not have second thought about you as you are a straightforward person. You can access anything in your chart in a stronger and easy way.
In Strategic Execution, is is consider as a good formation as the energy will be the purest where you can perform meditation or any Qi enhancement activities of sort. At this time, it is suitable for your energy realignments and gain a whole lot of clarity.

Fan Yin(反吟)
A Fan Yin Chart is different from a Fu Yin chart where the Stars and Doors are totally opposite of the Fu Yin Chart. The stem are the mirror in the opposite direction like a reverse pattern. Take a look at the sample below.
Generally it is considered more inauspicious than Fu Yin. Usually there are uncertainties in the matter being consulted and things might change. The outcome of the divination may come quickly and decisively. Where the impact of the outcome can be substantial or even extreme. It Usually favorable to the guests and unfavorable to the host. For examples, tasks might only be partially completed, trips might be cut short. The speed of events is fast in general, for example a verdict might come swiftly and unexpectedly. Incidents or events tend to occur far away, for example, one lost something far away from home.
In forecasting, when you get Fan Yin Chart (or Gua), there will be changes in matters asked. Matters will progress but not in the ways planned and there are possibility of things becoming good to bad and vice versa. There will be a lot of uncertainties ahead and thread only if you are prepared to face and handle all the adversities.
For Destiny reading, it can mean that the person always do the wrong thing(Door) at a wrong timing(Stars). They are alway either ahead of everyone or lacking behind, resulting doing the right thing at the wrong time when Star Fan Yin or doing the wrong thing at the right time when Door are Fan Yin. They will usually have hard time explaining their focus at that wrong timing but nevertheless, the key for them is to work on the things and make sure they can always be ahead of other and not lack behind.
While in Strategic Execution, you can make use of this formation to change the stagnation situation, creating movement or progress to be really ahead of everyone else.
A Fan Yin chart can be useful and positive if you need the opposite result of the current situation, so sometimes it is not so negative as it seems, you can use fan yin charts for extreme changes.

Hope that my sharing and understanding of Fu Yin and Fan Yin Chart can help those who still learning QiMen.