start a new document any size im using a 800x600
1. filters/render/clouds
2.filter/pixilate/mosaic and set to 35
3.filter/artisitic/fresco set at -brush size 0, brush detail 0, texture 3
4.duplicate layer then delete the locked layer named background
5.go to edit/transform/skew- drag bottom left to the left side and bottom right to the right side.

6.duplicate layer
7.go to edit/transform/flip vertical
8.change blend mode of top layer to lighten. shuld look like this.

9.merge layers togethor and change color or change color individually on each layer
this

or this

have fun...