Math Problem : KKK.10 Cutting line based on development view

When the cube of Fig. 1 is opened up by cutting by the bold line of Fig. 2, the development view become Fig. 3.

How should it be cut respectively, in order for the development view of each cube to become as shown in (1) and (2)?

As shown in Fig. 2, write a bold line in the sketch of the cube.


      

      
















Answer
(1) 

(2) 

Reference
(1)
(2)