Today's door leads to a signature "easy" puzzle by Anonymus25! I know, some of my recent puzzles haven't performed well (and by recent, I mean many months ago), but I'm back and ready to try again! As I said before, this puzzle is "easy", but only if you truly understand this genre's deductions. It's a Circles and Squares!
Rules: Shade some cells such that all shaded cells form one single orthogonally connected area, and no 2x2 anywhere in the grid may be fully shaded (as in Nurikabe). All unshaded areas must form squares. Black circles are shaded, white circles are unshaded.
Here's a Penpa link to solve online.
P.S. The green, red, and brown are purely for aesthetics.