Scratches node
The Scratches node outputs a fibers pattern, that can be used for scratches on any material or messy fibers.
It is inspired from a the Fuzzy scratches shadertoy from Daedalus (https://www.shadertoy.com/view/4syXRD).

Inputs
The Scratches node does not accept any input.
Outputs
The Scratches node generates a single grayscale output texture.
Parameters
The Scratches node accepts the following parameters:
the Length parameter defines the length of a fiber in the output texture. The number of scratches grows exponentially with the inverse of this length.
the Width parameter defines the width of each fiber.
Layers is the number of layers of the effect. The number of scratches grows linearly with the number of layers.
Waviness can be tweaked to draw straight or curved scratches.
Angle is the average angle of the scratches.
Randomness is applied to the scratches angles.
Example images
