Pretty_little_liars_3x06 ⚡

: This paper leads them to discover that a room was built into the sanitarium that wasn't on the official public records—a room that "A" (Mona) was using to sneak in and out of the facility.

: Spencer realizes the blueprint is dated months before the construction of that wing actually began. Pretty_little_liars_3x06

: It also deepens the mystery surrounding Toby’s mother, Marion Cavanaugh, suggesting that the "accidents" at Radley were planned or covered up long in advance. : This paper leads them to discover that

Another notable paper trail in this episode involves the Hanna finds in Wilden’s car, which places him in a different location than he claimed during the time of the "remains" discovery. Another notable paper trail in this episode involves

: While searching through a box of Toby’s things at the Apple Rose Grille, the girls find a blueprint for the "East Wing" of Radley.

Here is why that specific piece of paper was so significant: