#####
##### Robert Craigen 
##### W(8,5) is
##### I       H
##### H^T     -I
##### where H is any H(4)
#####

> W_8_5 := Concatenate(1,
>          Concatenate(2,IdentityMatrix(4),H_4),
>          Concatenate(2,Transpose(H_4),-IdentityMatrix(4))):

> writeto("W12.5.txt");