Because A, G, C, and T appear in the DNA, these molecules are called DNA-bases; A, G, C, and U are called RNA-bases. Uracil and thymine are identical except that uracil lacks the 5' methyl group. Adenine and guanine belong to the double-ringed class of molecules called purines (abbreviated as R).
Definition of decalcomania. 1  1 : the art or process of transferring pictures and designs from specially prepared paper (as to glass) 2  2 : decal.
There is also an element of unpredictability in the end-product, since it is not created stroke by stroke. The decalcomania trope recurs in the MV, such as in a top shot of Moonbyul dancing in a suit, and in other images of symmetry, like the mirror sequences. The lyrics point to decalcomania as a metaphor for two bodies pressing against each other during sex: You and I, same picture, I feel good.