2 x 4

(a)  

2 x 6

(a)  

2 x 7

(a)  

2 x 0

(a)  

2 x 9

(a)  

2 x 5

(a)  

2 x 3

(a)  

2 x 1

(a)  

2 x 8

(a)  

2 x 12

(a)  

2 x 10

(a)  

2 x 11

(a)