Gaslight falls au
Mabel is just as smart as her brother she just doesn't like showing it off. She also likes to be underestimated by others sometimes.
So imagine Ford absolute confusion when Mabel walks in and See's both Ford and dipper struggling with some equations.
Mabel: you forgot a two and that should be squared not divided.
Dipper in the know: oh thanks Mabel
Ford not in the know: blue screens. Looking at Mabel's eyes to make sure she is not possessed( see she is not) and turns back to the equation absolutely dumbfounded on what just happened.
Ford later See's Mabel trying to dress and makeup a feral raccoon.
Ford......?????????
I feel like i'd remind Ford even more Bill, Bill who would be able to correct calculations and matched him in intelligence...and then do insane bullshit.