import java.io.*;

public class Main{
    public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    }
    
    public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    }
    
    public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    }
} import java.io.*; io.* java public class Main{
    public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    }
    
    public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    }
    
    public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    }
} Main public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    } main {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) int count=0; count 0 while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        } true {
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        } String[] str = br.readLine().split(" "); str br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int h = Integer.parseInt(str[0]); h Integer.parseInt(str[0]) Integer.parseInt Integer str[0] str 0 int w = Integer.parseInt(str[1]); w Integer.parseInt(str[1]) Integer.parseInt Integer str[1] str 1 if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            } h==0 && w==0 h==0 h 0 w==0 w 0 {
                break;
            } break; {
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            } while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                } true {
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                } if(count==h)break; count==h count h break; System.out.print(write_odd(w)) System.out.print System.out System System.out write_odd(w) write_odd w System.out.println() System.out.println System.out System System.out count++ count if(count==h)break; count==h count h break; System.out.print(write_even(w)) System.out.print System.out System System.out write_even(w) write_even w System.out.println() System.out.println System.out System System.out count++ count System.out.println() System.out.println System.out System System.out count=0 count 0 String[]args args public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    } write_odd {
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    } String str =""; str "" for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        } int i=1; int i=1; i 1 i<w+1 i w+1 w 1 i++ i++ i {
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        } {
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        } if(i%2!=0){ str = str+"#";}
           else{ str = str+".";} i%2!=0 i%2 i 2 0 { str = str+"#";} str = str+"#" str str+"#" str "#" { str = str+".";} str = str+"." str str+"." str "." return str; str int w w public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    } write_even {
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    } String str =""; str "" for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        } int i=1; int i=1; i 1 i<w+1 i w+1 w 1 i++ i++ i {
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        } {
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        } if(i%2!=0){ str = str+".";}
           else{ str = str+"#";} i%2!=0 i%2 i 2 0 { str = str+".";} str = str+"." str str+"." str "." { str = str+"#";} str = str+"#" str str+"#" str "#" return str; str int w w public class Main{
    public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    }
    
    public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    }
    
    public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    }
} public class Main{
    public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    }
    
    public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    }
    
    public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    }
} Main
import java.io.*;

public class Main{
    public static void main(String[]args) throws NumberFormatException, IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int count=0;
        while(true){
            String[] str = br.readLine().split(" ");
            int h = Integer.parseInt(str[0]);
            int w = Integer.parseInt(str[1]);
            
            if(h==0 && w==0){
                break;
            }else{
                while(true){
                    if(count==h)break;
                    System.out.print(write_odd(w));
                    System.out.println();
                    count++;
                    if(count==h)break;
                    System.out.print(write_even(w));
                    System.out.println();
                    count++;
                }
                System.out.println();
                count=0;
            }
        }
    }
    
    public static String write_odd(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+"#";}
           else{ str = str+".";}
        }
        return str;
    }
    
    public static String write_even(int w){
        String str ="";
        for(int i=1;i<w+1;i++){
           if(i%2!=0){ str = str+".";}
           else{ str = str+"#";}
        }
        return str;
    }
}