Toady let me introduce you to a new art form called Zentangle.
I discovered this art form a few days ago and I am hooked to it.
You can do this anywhere and materials required are pen,paper and imagination.
In Zentangle you create images using repetitive patterns.
The art form helps to give vent to your creativity and increases your ability to concentrate and helps in relaxing.Although it require patience it is enjoyable and fun to do.
You can google search this art form and get inspiration to do designs of your choice.
Do try this art form which can be done while travelling in plane,on holidays anyplace anywhere.