Take this simple show/hide game and make it your own.
The starter project provides a simple example that displays a specified number of targets for the specified time (in ms).
The player tries to remember where the targets were and click them to get points.
There are many ways that this game can be improved. Not only can you style differently, but the starter version is missing several features you would expect in a typical game like this. It's up to you to implement them!