To apply the idea of wear and tear to the interior as well, I made a jeans carpet with indigo blue dyed yarn. With this you could emphasize the walking route in a shop or home, like a sort of “elephant trail”.
As a rule, a worn look is not appreciated in wall to wall carpet. For an alternative I washed a sample. At the top the colour has faded out by washing and will not wear any further, but in the base, the dark, deep, full indigo blue colour is still present.
Yarn dyed with indigo.
Since the pigment is not absorbed by the fibre, a cut pile gets a light (undyed) tip at the core of the yarn.
That same effect could be attained with a dyed woollen yarn where the pigment does not reach the core of the yarn, but that process is hard to control.
Yarn dyed with indigo, the pigment attaches to the fibre but it does not soak into the fibre. That is why it is easy to rub, or wash the colour off. Think of worn, faded jeans.