Converting a single column vector to a 4d vector.

Dear

Following my previous question which jos has shown me how to solve), i got struck in solving the opposite problem.

input:

a(1,1)=051

a(1,2)=0.55

a(1,3)=0.67

output:

a(:,:,1,1)=0.51

a(:,:,2,1)=0.55

a(:,:,1,2)=0.67

thanks,