Create a quick shape layer in black or it can be filled with an image or gradient etc.
Go to the filters menu and colors and halftone and then set the screen to color and dot to cosine and cell size (to a reasonable size) and contrast to about the mid point. Set the under color removal to a large value and mid point for the gray component etc though the settings depend on the source design that you are using. Youtube video on subject
Go to the filters menu and colors and emboss and set radius to 100px or 200px etc and set the amount to the mid point and set the rotation as required. You can also repeat the filter over and over Youtube video on subject
You can also blur the design by using the filters menu and blur and Gaussian blur etc Youtube video on subject
With the layer selected, go to the layer menu and new pattern layer from selection, set the mirror option in the top left to ON. Re-size the pattern layer and rotate etc. Youtube video on subject
Go to the filters menu and distort and deform and set the handles and set to similarity etc and distort the layer and colors. Youtube video on subject