After the girls return from the alien potato ship, they return to Gran's House by climbing up to their window. From the outside of their room, it is of a hexagon shape with no straight walls. However, when seen from the inside, it is a large bow window with straight walls.
The kitchen of Gran's house appears to be located at the back. However it appears to be located at the front in the diagonal room when the girls see the potato babies in their high chairs.