turbulence attribute
// pattern modifier
// Takes a float or vector for selective turbulence in different directions
turbulence <0, 1, 0.5> // how much to 'stir up' the texture (0...1 or more)
// (---additional parameters influencing style of turbulence---)
lambda 2.0 // (1.0...5.0) (smooth...random) [2.0]
omega 0.5 // (0.0...2.0) (crinkly...fuzzy) [0.5]
octaves 6 // number of folds in turbulence (1...10) [6]