dualistic

coupled dual duple duplex duplicate geminate paired twin twofold

as much again binary binate twice two times

singular

single

corresponding duplex equal equivalent same twin

alike carbon-copy duple identic identical indistinguishable self-same tantamount twofold very same

different dissimilar mismatched unequal unlike variable

unmatching

amphibian binary diploid

amphibious bicameral bifurcate bigeminal bilateral binal bipartisan bipartite bisected dichotomic dichotomous distichous dual dyadic