I'm not sure how long it would last but how about something like a bubblegram [1] (laser crystal)... You could use a flatter plastic block and create a 2D image

I'm not sure how long it would last but how about something like a bubblegram [1] (laser crystal)... You could use a flatter plastic block and create a 2D image inside. Also, maybe other materials can be used. 1. https://en.wikipedia.org/wiki/Bubblegram https://en.wikipedia.org/wiki/Bubblegram