CHECK: [step 0] initial array
CHECK-NEXT:        1        1        1        1 
CHECK-NEXT:        1        1        1        1 
CHECK-NEXT:        1        1        1        1 
CHECK-NEXT: [step 1] scan horizontally
CHECK-NEXT:        1        2        3        4 
CHECK-NEXT:        1        2        3        4 
CHECK-NEXT:        1        2        3        4 
CHECK-NEXT: [step 2] transpose array
CHECK-NEXT:        1        1        1 
CHECK-NEXT:        2        2        2 
CHECK-NEXT:        3        3        3 
CHECK-NEXT:        4        4        4 
CHECK-NEXT: [step 3] scan transpose horizontally
CHECK-NEXT:        1        2        3 
CHECK-NEXT:        2        4        6 
CHECK-NEXT:        3        6        9 
CHECK-NEXT:        4        8       12 
CHECK-NEXT: [step 4] transpose the transpose
CHECK-NEXT:        1        2        3        4 
CHECK-NEXT:        2        4        6        8 
CHECK-NEXT:        3        6        9       12