In brief: Intuitive STEM-challenge-fun approach to optics and symmetry.
Inside are all the highlights of what I teach in my physics high school physics class, made super fun.
So this really can be used as a fun supplement in any curriculum.
For example: the symmetry task cards move from super basic, to challenging even for an adult.
Note: you will need small mirrors for these activities!
If you're interested in the "big brother" of this resource, the actual teaching that goes on when I'm not busy having fun, check out diffusion, reflection and projection.