Cut cold boiled potatoes in one-half inch cubes. Sprinkle four cupfuls with one-half tablespoon salt and one-fourth teaspoon pepper. Add four tablespoons oil and mix thoroughly; then add two tablespoons vinegar. A few drops of onion juice may be added, or one-half tablespoon chives finely cut. Arrange in a mound and garnish with whites and yolks of two hard-boiled eggs, cold boiled red beets, and parsley. Chop whites and arrange on one-fourth of the mound; chop beets finely, mix with one tablespoon vinegar, and let stand fifteen minutes; then arrange on fourths of mounds next to whites. Arrange on remaining fourth of mound yolks chopped or forced through a potato ricer. Put small sprigs of parsley in lines dividing beets from eggs; also garnish with parsley at base.