Many sets got little tweaks over the three seasons, but Engineering feels like it was almost a personal project for Matt Jefferies, growing from that bare room with a few odd looking things in the middle of it in "The Enemy Within", to being that elaborate multi-story set with lots of visual interest by the third year. It's almost like, every time a new season started and there was just a little more give in the budget, he would refine it.
Exactly. And as you might expect from someone with an interest in engineering!
One of the things I love about S3 is that we learn so much more about the Enterprise and how it works.