{
	Calculation of picture coordinates for cabin roof shakes.
	Shake_u (x-coordinate) is supposed to be aligned with roof length,
	and uses smooth noise function, whereas shake_v (y-coordinate) uses
	fractal noise function to give rough edges to the shakes.

	A1		- Ratio of height to width for tiles.
}

shake_u = mod(Px+.1*noise3(Px,Py,Pz),max(1,1/A1));
shake_v = mod(Py+.05*fnoise3(Px,Py,Pz),max(1,A1));

