It's masking Jim

but not as we know it!

Another one of the sections from Gill's travelling book of fabric art creations. This time on the theme of masking.   You can see both pages in the extra.  The idea being the whole of the right hand page is not seen, but by moving the mask small sections are revealed.
Each page is a ~200mm square.

In the dictionary definition on the left, photomask does make a one word appearance.

alternatively: One us us is creative, the other one takes photographs!