introverted perception is to use an object, to anker something subjective in it. the subjective thing does not have to be personal and it does not have to be unreal. (but it is often. it could be ethnocentric, or human .... subjective)
to anker a state of mind or being into a symbol is indeed one possible version of introverdet perception.
so when cinnamon reminds you of christmas, this is a normal memory, and you could indulge in it often for emotional resons (navigated by cognitive Fi), but once you begin to paint an image, using cinnamon instead of brown color, because your image is about the birth of christ and the depicted religious image feels more alive to you, when painted with cinnamon, then this is an example of introverted perception.
another example is carrying around a toygun, not larger than a piece of money (ie playmobile), not intending to practically play with it, not to remind you of either playmobile or childhood, but to evoke the feeling of being like a cowboy, which also coincidentally happens to be a memory, since you learned about the cowboy feeling in movies, which you have seen in the past.
it is subjective!!! you may carry around a toygun for any other amount of reasons, same for using a spice in a painting
to subjectively anker a sense of greateness or decay or evolution of society or being a servant (what ever you want) in an item like an uniform may also be Pi
the difference between Pi and what everybody else does, when they are using symbolic ankering, is that Pi is verry conscious and individualized about what somethign means to them, while other people mostly addopt the common sense symbolism, and dont give much thought to it. to most people a unifrom is stricktly about bein a member of the military, nothing else, exept they may have personal feelings about what it means to be a member. the Pi user does not have to be a member, he may wish to wear a uniform for subjective reasons, even when he does not even theoretically like to be a member. it may be pure irony to him. obviosly many fashion trends (like punk) are invented by Pi (and imitated by Pe). the Pi user feels alienated and de-personalized, if his subjective symbolizm is taken away/argued/misunderstood, because he fears loosing himself, loosing touch with the motives of his soul. or, of collective soul. because, as i said, subjective does not have to be personal.