It has been argued that the symbols between these two passages are just too different for them to be referring to the same time period. The passages contain both similarities and differences, so when the symbols do differ it must be asked if the meanings behind those symbols are contradictory or complementary. I believe the latter to be the case, yet here are the parallels, both thematic and linguistic:
The left column indicates the parallel theme present in both Revelation 12 and 20, and the two right columns show the linguistic parallels in Greek (See especially the underlined portions). It might be helpful to look up these passages side by side and see what I am talking about.
Note also the correlation between these two passages and John 12:31. I’ll be posting on that next.