I saw a Magic Window when I was sitting in a small waiting room around 1973 or 1974 and thought it was kind of fun, so I eventually got one. It wasn't the greatest toy in the world, but it was fun to mess with once in a while. It was like playing with ocean waves. It was a stress relieving toy where the only purpose was to make patterns (similar to the Space Fidgit).
It took me until 2005 to find the name of it. I remembered that it seemed to have blue and white 'sand' inside of a clear thin plastic oval, but that's all I could remember. The name of it never stuck in my head. I also never knew there was a pink and white version back then.
Here are two related YouTube videos:
(As an Amazon Associate I earn from qualifying purchases. I get commissions for purchases made through certain links.)
Amazon sells a bunch of #ad similar-looking toys, but none of them look quite right to me. Maybe you can find one that's close enough.
Below are a few pages that have more information and images: