In all the talk of graphical downgrades no one seems much preoccupied with 'why?'. Why build something and then proceed to tear it down, piece by piece, in the hope that ever more diminished expectations about the final product won't be severe enough to...
When you get stuck with what to do call on Mechanic Pig and it will instantly build the best possible vehicle for a specific puzzle. You'll still need to ferry the pig to the end of the stage while reaching the assigned goals.
You can score three Mechanic Pigs by liking Bad Piggies on Facebook. When those run out, buy more via in-app purchase:
10 Mechanic Pigs: $1.99
35 Mechanic Pigs: $5.99
65 Mechanic Pigs: $9.99