Night lights have been great gifts for my kids friends.  It took a little while to figure out how to engrave clear acrylic.  I tried tempera paint that was recommended, but I couldn't get it to adhere well.  What I ended up with was spray painting black paint onto an aluminum plate that I put under the clear acrylic piece. I tried with black anodized aluminum and it did not work as well either. I focused the laser to the top of the painted aluminum and then used scoring instead of engraving.  The engraving gave a lot of variability.  I'm sure I could dial it in in the future, but I was really happy with how scoring came out. And, it is easy to take files and trace them using Inkscape to make them ready for engraving. I licensed the ladybug file from Adobe Stock: https://stock.adobe.com/images/coloring-book-with-ladybug-vector-illustration-isolated-on-white/131176191?prev_url=detail
I bought the night light kit from Amazon.