The number of veins layers is defined by the Octaves parameter. Higher octaves feature smaller veins than lower octaves. By decreasing the Persistence attribute, you can fade out the higher octaves. Increase the Resolution parameter to reduce the overall vein size.

By setting the Persistence value to greate than 100, you can abuse the function to create plaster-like textures.

Regulate the intensity of the veins with the Amplify value.

Change the Random Seed attribute to get a different veins pattern.

You can animate the three-dimensional veins texture by increasing the Time Offset value. This will move the virtual camera along the z-direction into the texture. After 1000 time frames you will reach the starting point again.