Origami

Fold skypoint 1 along roofline A, towards Buildingpoint 3 . Open, and fold BuildingSkypoint 2 towards BuildingSkypoint 4 in the same manner.

Fold each point towards the middle, along the lines you just created. Open 1 of the 4 triangles, and fasten the other 3 to each other using cello tape of the likes.

Insert second copy of the same picture, and clos the last corner. Fasten the corner.