(taken from website)

DNA Painter is a website for genealogists and family history enthusiasts who have taken an autosomal DNA test.
Interpreting test results can be a challenge. DNA Painter helps by providing a platform where you can:

•  Take stock of what you already know about your family line by building or importing a tree.
•  Use the amount of DNA you share with matches (measured in centiMorgans) to look at how you might be related to them with   interactive tools
•  Try chromosome mapping to visualize the actual segments of DNA you share with matches to deduce which parts of your DNA you   inherited from specific ancestors in your tree.