Patterns of Features Used to Establish a Datum, Part 1 of 3

The Y14.5 standard tells us we can use a pattern of features to establish a datum (Y14.5-2009 paragraph 4.12, Y14.5-2018 paragraph 7.12). The pattern of features may be specified using one datum feature letter or a hyphenated list of datum feature letters, termed a “Multiple Datum Feature” in 2009, or a “Common Datum Feature” in 2018.