RNAs and their assemblies can form diverse nano-structures and nano-shapes, offering various biological functions. However, by simply mimicking RNA sequences, DNAs cannot normally form the corresponding nanostructures, which makes the nature-inspired transformations and designs challenging. To understand the possible designs and connections between related RNA and DNA nano-shapes, herein we have reported several DNA squares transformed and derived from an RNA assembled square, by gradually replacing RNA with DNA nucleotides. We have found that there were key RNA nucleotides: Their presences maintained the square, while their absences disrupted it. Interestingly, we have revealed that as long as the conditions of higher ionic strengths or longer duplexes were included, the square RNA assembly could be completely replaced with DNA nucleotides, still offering the stable DNA nano-shapes. Our experimental results have demonstrated that similar RNA nanostructure can be easily transformed into DNA ones via designing and increasing ionic strengths or duplex lengths.