I just saw this set all about Goethe’s experiments with colors in the 1790s at manufactum. Made for children to play with and think about how we perceive color, the set comes with a variety of beautiful color cards and a prism for all sorts of experimentation. My German isn’t perfect, but I think it also comes with Goethe’s original publication “Beyträgen zur Optik” as well as an additional booklet with more things to do with the prism. At 49 euros, it’s a bit steep, but a beautifully designed and really fun looking toy. Manufactum also has a magic lantern, a kaliedoscope, and tons of other really interesting and unusual toys.