A method having steps of (a) providing nucleic acids having a tag sequence (N1)n(N2)n . . . (Nx)n, wherein N1, N2 and Nx are nucleotides that complement different nucleotides, respectively, wherein n is an integer that can differ for N1, N2 and Nx; (b) detecting the nucleic acids individually and under conditions to distinguish signal intensities for (N1)n sequences having different values for n, (N2)n sequences having different values for n and. (Nx)n sequences having different values for n; and (c) distinguishing the tags based on the signal intensities.