Sheltie puppies inherit characteristics from their parents.
Individuals also have genes.
Each Sheltie carries two copies of each gene, one from each parent. Sheltie Coat color is controlled by more than five genes, three of which are probably the most important. Let's pretend that two genes explain the inheritance of Sheltie coat color. This ignores the a number of complexities . We can ask what the coat colors would be expected in Sheltie puppies produced by different combinations of parents.