1) Open a new document any size will do, make sure the colour pallet is set to default (black and white). Then we do a cloud filter.. 'Filter' > 'Render' > 'Clouds'



2) 'Filter' > 'Render' > 'Difference Clouds' - repeat this step 2 MORE times:



3) 'Filter' > 'Artisic' > 'Cutout' - change the values to: (number of levels:8; edge simplicity:5; edge fidelity:3) now click ok.



4) To add colour.. we bring the hue/saturation window up - do this by clicking 'ctrl and u'.