Puppies have a tendency to eliminate in exactly the same spot over and over. When you go observe Boston puppies for sale, you might see some colors in a litter. Some Boston puppies for sale aren't purebred
"Like many other much-loved humans, they believed that they owned their dogs, instead of realizing that their dogs owned them." -- Dodie Smith, The Hundred And One Dalmatians. The original Dodie Smith book is SO much better than the disneyfied version.