There are different senses of "forwards and backwards". There's nothing particularly wrong with yours, there's nothing particularly wrong with the other one, bu

There are different senses of "forwards and backwards". There's nothing particularly wrong with yours, there's nothing particularly wrong with the other one, but they aren't the same. "Reversible computing" here means that you can run it backwards in the sense of undoing what was done by running it forwards. You're talking about data flowing in opposite directions, while in every case your program runs forwards doing its thing.