Variable cannot have type 'void'

 element < whole ...I, whole ...J>
 The regular pattern   dynamic   Phase transformation ( Sequence <I...>a, Sequence <J...>b){
    
     conclude ( Type length, etc (I,J)); The regular pattern   whole  K= Take the head (b);
     Phase transformation ( Sequence < Take the head (a),K>(), Head off (a), Head off (b), Sequence <K>());
}// Relative offset to absolute , The front is multidimensional , Followed by relative offset .

Then keep reporting Variable cannot have type “void” error !
Oh dear , Say half a day , Just forget return 了 .
Just add... To the last sentence in . It's , Looking for half a day , Can't find the reason .
Forget to add in 了 .