So, I was watching Season 2 of Gravity Falls and I was watching "A Tale of Two Stans" and I found this:

(Yellow writing was by me)

And when you flip it right side up/upside down..

HOLY S----!!!
I SAW THAT ALMOST IMMEDIATELY!
This is a reference to the Diamonds from Steven Universe!
Does this mean that G.F and SU are somehow connected?!