Place the pieces on a flat surface and hide one piece under the other four. Only one piece can be hidden so.
I introduced Cover Girl at the New York Puzzle Party in May 2023. It is a sequel to Cover Up, my entry in the 2019 Nob Yoshigahara Puzzle Design Competition.
Thanks to Joyce Michel for suggesting the name.
I made the set shown above from precut wooden cubes, glue, and acrylic paint.