Just turn on a source of light behind the product and 'the scream' will come alive :o (spookier at night ;) )
A lithophane is a 3D image, that changes according to the intensity of light striking it. The light areas are very thin, allowing more light to pass through, while the thicker areas appear darker.
FDM or SLA printer.White colour ABS or PLALayer height 0.1-0.2 mmInfill 100%