While the facet count is standard, the actual proportions—"crown height" and "crown angle", "pavilion depth" and "pavilion angle", and "table size"—are not universally agreed upon. There are at least six "ideal cuts" that have been devised over the years, but only three are in common use as a means of benchmarking. Developed by Marcel Tolkowsky in 1919, the "American Standard" (also known as the "American Ideal" and "Tolkowsky Brilliant") is the benchmark in North America. It was derived from mathematical calculations that considered both brilliance and fire. The benchmark in Germany and other European countries is the "Practical Fine Cut" (, also known as the "Eppler Cut"), introduced in 1939. It was developed in Germany by empirical observations and differs only slightly from the American Standard. Introduced as part of the Scandinavian Diamond Nomenclature ("Scan. D. N.") in 1969, the "Scandinavian Standard" also differs very little.