At some point, you might want to have a curved wall. That can be done by splitting the wall into several pieces and forming a semicircle like this:
The smaller wall particles are the smoother the semicircle will be.
To split the wall into smaller pieces you need to tap on it and use a splitting icon.
Check out our video tutorial on how to create a curved wall. We're using the Web version on that video. However, main controllers are the same for all apps, so you won't have any difficulties reproducing these steps on your device.