Corian is a solid surface acrylic material, which carves beautifully and is great for making really dynamic deep contrast lithopanes.   It is sold in sets of two sheets each ¼” thick with your choice of color and size.

Cast acrylics are hard plastic products for making lithopanes or plastic cutout parts. .   It is sold in sets of two sheets each ¼” thick with your choice of white or clear and size.