It is a 3D architectural simulation of Tadao Ando design Sumiyoshi of tenement.
You will move to the front, rear, left and right by moving the lower left corner of the circle.
Line of sight is the direction up, down, left and right by moving the circle at the bottom right.
It will jump when you tap the bottom center. It goes up to the roof.
Sunlight is also movement from time to time.