Mandalas are spiritual symbols from Hinduism and Buddhism that represent the universe and the transient nature of life. They are often created with various coloured sands by Tibetan Monks as a visual aid during meditation. You can read more about Mandalas @ Wikipedia.
On that note: Here is a series of 100% hand coloured Mandalas for some mid-month inspiration! You are more than free to use these as desktop or smartphone wallpapers!
All the art pieces on this page are derivative works from colouring pages/books and thus are protected under a CC-by-NC 3.0 licence. Therefore they can only be used for personal and non-commercial purposes. Please consider giving attribution to All Natural Spirit (https://allnaturalspirit.wordpress.com) when used for purposes other than personal wallpapers. Thanks!