The present disclosure includes methods and apparatuses for mapping between program states and data patterns. One method includes: programming a group of G memory cells such that a combination of respective program states of the group maps to a constellation point corresponding to a received N unit data pattern, the group used to store N/G units of data per memory cell; wherein the constellation point is one of a number of constellation points of a constellation associated with mapping respective program state combinations of the group of memory cells to N unit data patterns; and wherein the constellation comprises a first mapping shell and a second mapping shell, the constellation points corresponding to the respective first and second mapping shells determined, at least partially, based on a polynomial expression of order equal to G.