- You may be looking for the titular model.
The Way Forwards was a 2011 Big Finish Productions audio short story. It was read by David Troughton and featured the Second Doctor, as played by his late father Patrick Troughton in the television series.
Sherman Pegg is participating at a science fair, along with three-hundred and fifty-nine other students. Sherman in unwillingly there, his mother having pressured him into enrolling and the fair being biased, with Sprag High School having the benefit of a former pupil as head of the judging committee. Sherman's entry is based on a theory of time travel and is officially called A Way Forward.
Sherman notices as the Second Doctor and Victoria arrive, observing their odd clothes and the way they look at the entries. Sherman talks to the Doctor, realising that he has found someone who understands his theory.
After requesting permission to make a suggestion, the Doctor makes alterations to Sherman's formula. Suddenly, the boy vanishes and the Doctor realises he understood the changes better than expected and has altered history so that he never attended the fair. Their surroundings change from a mall to a field, to a parking lot, then a forest on fire, underwater, and then back in a field.
The Doctor and Victoria make their way back to the TARDIS. They exit and find themselves on a black rock. Ahead is the Summer Park Mall. The Doctor finds several versions of Sherman from different points in his personal timeline.
Holding a hand each, the Doctor and Victoria take the twelve year old Sherman back to the TARDIS, with the former telling him, once he reversed Sherman's alterations, together they are sure to come up with a winning entry for the science fair.
- Sherman uses a basketball in his A Way Forward model. He originally wanted to use a meatloaf.
- Sherman claims Albert Einstein "lost it with that whole three rivers concept" and that string theory is "too linear".
- Sherman creates a paradox, preventing his attendance to the fair where he was given the secret of time travel.
- There are talking gorillas in the world created by Sherman's meddling with time.
- Although officially titled as The Way Forwards, Troughton reads it without the final consonant.
- It is remarked upon that Sherman does not say "it's bigger on the inside", when he enters the TARDIS. (TV: Smith and Jones)