They combined the two shots to make it look like the car’s wheels were flaming.

Jeffrey Okun: I know the guy who did that car! What they did was, they drove a car down the street, then put gasoline on the street and lit it on fire, and filmed that. I know it was impressive at the time, but now it looks terrible. Re/code quizzed him about a few key effects in “Back to the Future Part II.” He worked on “Stargate,” “Sphere” and Wes Craven’s “Shocker,” among many other films, and has an encyclopedic knowledge of Hollywood trivia. We spoke to Jeffrey Okun, who has chaired the Visual Effects Society in Los Angeles, Calif., for the past six years.

It’s fun to watch these movies now and marvel at yesteryear’s future, but instead of scrutinizing the tech that didn’t happen, we thought it’d be more interesting to look at the movie tech in 1989 compared with 2015. As if the Star Wars trailer hadn’t made this week geeky enough, today is October 21, 2015, the day Marty McFly time-travels to in the second installment of the “Back to the Future” movies, which came out in 1989.

Back to the future flame trails