
According to the rule of tincture, one of the fundamental rules of heraldic design, colour may not be placed on colour nor metal on metal (in heraldry, "metal" refers to gold and silver and yellow and white, which are often used to represent gold and silver. "Colour" refers to all other colours). Sometimes, however, it is desired to do something like this, so fimbriation is used as a method of getting around the rule.
In the arms of Mozirje, in Slovenia, is an example of fimbriation that itself is fimbriated. 
In vexillology that is not specifically heraldic, the rules of heraldry do not apply, yet fimbriation is still frequently seen. The reason for this is largely one of visibility - the separating of darker colours by white or yellow is an aid to the visual separation of the darker colours. A good example of a flag which uses fimbriation is the national flag of South Africa which is fimbriated in white above and below the central green area, and in yellow between it and the triangle at the hoist.
Some fifteen to twenty countries use fimbriation on their national flags. National flags that use fimbriation include those of Trinidad and Tobago, North Korea, Botswana, Kenya and - most famously - the British Union Flag. The flag of Uzbekistan uses a very unusual form of "pseudo-fimbriation" - it adds a thin red band between a colour and a metal, separating blue (above) and green (below) from a central white stripe.