The I Ching is traditionally used for divination.
An I Ching divination using the three coins method would go as follows:
Prepare three identical coins with two distinct sides. Choose one side to represent yin and the other side to represent yang.
If you wish, ask a question. The question should be relating to a situation and open ended.
Questions like "What is the situation regarding...?", "What are the possible effects of...?", "Which are the choices present regarding...?" would be examples of such questions.
("What are my/your views/opinion on...?" would be an interesting alternative.)
There might be no need for an explicit question, but it should be clear in what context the divination is taking place.
Toss all three coins. There are four possibilities:
3 yin sides (1 in 8 probability) - old yin
2 yin sides, 1 yang side (3 in 8 probability) - new yin
2 yang side, 1 yin side (3 in 8 probability) - new yang
3 yang sides
(1 in 8 probability) - old yang
In the I Ching, extremes are considered unstable, so old yin and old yang will soon change into their opposites: new yang and new yin.
New yin is marked as a broken line and new yang as an unbroken line. Old yin and old yang have the marks 'X' or 'O' in the middle to represent the changes to come.
The coin toss takes place six times; once for every line in the resulting hexagram.
This changing hexagram represents two situations: one before the change (when old yin and old yang are still yin and yang) and one after the change (old yin and old yang grow two old and revert to their complements).
The I Ching text is consulted for each of the two hexagrams, with emphasis on the changing lines.
The divination process is complete upon reflecting on and understanding the insights received.
In the I Ching, yin is represented by the number '2' and yang is represented by the number '3'. So, old yin is '6', new yin is '7', new yang is '8', and old yang is '9'.
The three-coin toss can be used to answer yes-no questions as well; yin is 'no', yang is 'yes', new is a standard answer, and old is an answer with an emphasis.
There are other various methods for determining the hexagram beside the three coins method. The most notable of these is the yarrow stalk method, which gives different and asymmetric probabilities as result.
Even if the I Ching system is not used for divination, I think its versatility and dynamic use is worth noting.