How to do it
Paint the panel in a light colour.
While the paint is wet, make small lines in a darker colour, use the basic colour to even out the colour.
Make prints from the weels of a legocar, lace ribbon or what ever you like.
Write a text with the use of a Lettering stencil and a permanent marker.
Make prints by using nut, small felt figures or what ever you want.
Paint screws, bolts, nuts etc in a strong colour.
Make barbed wire by winding bonzai around it self and nip off the ends.
Glue the things on the panel.
Attach the barbed wire to the panel using glue.
Attach the plate in the frame.