Switching Window / window

Switching Window is concept the blind is inside of window-frame. So using blind easily without extra installation or equipments.
There is roll blind which is rolled up in the frame of inner-window, end of the blind is connected to the frame of outer-window. So, it disappears when windows are closed and it appears when windows are closed to the opposite position.
Switching Window doesn't need any string and it is easy to maintain by attaching and detaching roll blind easily.