A free app for Android, by Severex.

POLYGON: Coloring-Book is an awesome color-by-numbers app. This coloring game will provide you with the opportunity to explore beautiful artwork and have fun at the same time. You will be able to color by numbers, so it’s not only a game for kids but also a great way for adults to relax and enjoy their time.

You can use this app to create different artworks, such as a mandala, a flower, a landscape, etc. It is very easy to use and you will not need any special skills to create amazing artwork. Moreover, it does not require an Internet connection.