If having a sign reading "SMITH AND CO." painted, were you to write out directions for the signpainter that the sign "is to read 'SMITH' and 'AND' and 'CO.'", it would be beneficial to use single quotes between 'SMITH' and 'and', and 'and' and 'AND', and 'AND' and 'and', and 'and' and 'CO.' for clarification.