Photochromic (color change with UV light).   UV reactive coating makes the color change possible.  When UV light hits the material, either by going outside, near a window or even just shining a UV pen on it, the color will change from the off-white base to show a really cool orange paisley/bandana type print.   When in direct sun, the change happens quickly and color is much stronger!  

This is an example of what you can do by masking a pattern on the other solid materials and painting the base color!