Facebook appears to be eyeing even more expansion in Redmond, Wash., where it has amassed a sprawling campus near Microsoft’s headquarters.

Citing documents obtained through a public records request, the Puget Sound Business Journal reports that the social giant is in the early planning phases for a 650,000-square-foot, two-building office project for its Facebook Reality Labs/Oculus division. The site of the project is along Willows Road, where Facebook is snatching up buildings left and right, on two parcels it bought earlier this year for $20 million.

Under the mysterious moniker “Building X,” the project could kick off with demolition in May. No permits have been filed yet, and plans for the project could have been revised, but documents obtained by PSBJ indicate that Facebook hopes to open the new building or buildings toward the end of 2021.

Facebook declined to comment.

Facebook has yet to quantify the size of the rapidly growing campus in Redmond, but GeekWire research pegs it between 350,000 and 700,000 square feet. This project could put that campus at or above 1 million square feet.

Oculus has been on a hiring spree to fill up that space, and it lists 170 open positions in Redmond on its job board.

Facebook also has leased space in two downtown Bellevue office towers and is eyeing a project in the Spring District development. At the same time, Facebook will occupy a 384,000-square-foot, $246 million office project in the South Lake Union neighborhood in Seattle.