Trying to create a little white square in a procedurally turbulent procedurally yellow colour cloth-like material like the reference.(image1)

I think i've got the right nodes in the right area, doing the right things (image2) but nothing is changing in the render.

I'm using plain old white and black images to show where I want the white square, and whether i use white on black or black on white, nothing changes. (image3)

help