The "Melting Pot"
The primary metaphor for assimilation has been "the melting pot." That is, the American experience of public schools, intermarriage, common language and ideology "melt" our differences as though they were blended in a great cooking vessel. The product of the melting pot is "the new person" or "American" who bears no marks of ethnic or tribal identification.
Minorities may find the melting pot metaphor racially limited and so prefer other metaphors like “the rainbow” or “a quilt.”