Punctuation the marks hierarchically, in terms of weight". Cecil Hartley's poem identifies their relative values: <poem style=margin:4em;> The stop point out, with truth, the time of pause A sentence doth require at ev'ry clause. At ev'ry comma, stop while "one" you count; At semicolon, "two" is the amount; A colon doth require the time of "three"; The period "four", as learned men agree. </poem> The use of punctuation was not standardised until after the invention of printing. According to the 1885 edition of "The American Printer", the importance of punctuation was noted in various sayings by children such as: <poem style=margin:4em;>
Serial comma can also be written in other ways that eliminate the ambiguity without introducing the serial comma, such as by changing the word order or by using other punctuation, or none, to introduce or delimit them (though the emphasis may thereby be changed): An example collected by Nielsen Hayden was found in a newspaper account of a documentary about Merle Haggard: A serial comma following "Kris Kristofferson" would help prevent this being understood as Kris Kristofferson and Robert Duvall being the ex-wives in question. Another example is: It is unclear whether the eggs are being grouped with the bacon or the