It is a typical example of ELO's (at the time) cutting-edge use of technology and recording techniques, which would become the conventional sound of pop music within 10 years.
The middle section contains drums and electronic percussion created by a then state of the art Moog processor, and continues with rising intensity.
According to ELO drummer Bev Bevan (regarding the Moog processor): Uh, yeah, I used it on one track on the album, So Fine.
Jeff Lynne (August 21, 1990 - Classic Albums radio interview by Roger Scott)[1]Regarding the dropping end of So Fine to segue into the next song on the LP, Livin' Thing: "(It) was getting the two track and - and just basically switching it off, y'know, the motors off.
Jeff Lynne (August 21, 1990 - Classic Albums radio interview by Roger Scott)[1]In the book about ELO, Unexpected Messages, the authors expounded: "The end of the song So Fine fades into Livin' Thing.
This was created by unplugging the tape machine and when it got to the key 'A' (which starts off Livin' Thing) Jeff cut it."