The term Overo is, for some strange reason, used to include Sabino, Splash and Frame, even thought the three patterns bear no more genetic similarity to one another than they do to Tobiano which is the fourth pattern. So a Tovero would be the combining of Splash, frame and Sabino, to Tobiano. Since there is no test for Splash or Sabino as yet, it is pretty much guesswork, in some cases!!! It is possible, if you know what you are looking for, to be able to discern what patterns are included in a horse. I much preferr to actually describe the horses patterns- is Sabin/Splash or Tobiano / Sabino, than to use a blanket term such as "Tovero"- which, to me, means very little.