//itp1_topic5_c
#include <bits/stdc++.h>
using namespace std;

int main(){
   while(1){
     int H, W;
     cin>>H>>W;
     if(H == 0 && W == 0)  break;

     for(int i=0;i<H;i++){
        for(int j=0;j<W;j++){
          if((i + j) % 2 == 0) cout<<"#3 4

          else cout<<".";
          }
          cout<<endl;

        }
        cout<<endl;
 
    }

    return 0;
}
