Abstract: A method of making cellular or expanded polymeric shaped articles having relief patterns which comprises forming a thermoplastic polymer composition containing azodicarbonamide as a chemical blowing agent into a desired shape, irradiating a surface of the shaped body thus obtained with light of wave lengths of 100 to 500 m.mu. through a printed pattern applied thereto or a screen which locally shades light rays, such as a stencil or a positive or negative transparency, superposed thereon and heating the shaped body to effect foaming or expansion thereof.