My Mom gave me a plastic 15 Puzzle for Christmas. This inspired me to create a web app where I could play it on my phone or desktop computer.
I developed this with Dart and Flutter. I can see how they can be really useful in creating apps that have to be uniformly displayed across web and as stand alone web apps. Both are very good for that.
This one page website includes a timer and move count. I had to watch a YouTube video to learn how to play - otherwise it is almost impossible to solve without having a plan. You can view the YouTube instruction video below:
Play 15 Puzzle