import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    }
} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    } main {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        } true {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        } int a = scanner.nextInt(); a scanner.nextInt() scanner.nextInt scanner int b = scanner.nextInt(); b scanner.nextInt() scanner.nextInt scanner if (a == 0 && b == 0) {
                break;
            } a == 0 && b == 0 a == 0 a 0 b == 0 b 0 {
                break;
            } break; for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            } int i = 1; int i = 1; i 1 i <= a i a i++ i++ i {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            } {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            } for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                } int j = 1; int j = 1; j 1 j <= b j b j++ j++ j {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                } {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                } if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (i + 2) % 2 == 1 (i + 2) % 2 (i + 2) i 2 2 1 {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 1&&j!=b (j + 2) % 2 == 1 (j + 2) % 2 (j + 2) j 2 2 1 j!=b j b {
                            System.out.print("#");
                        } System.out.print("#") System.out.print System.out System System.out "#" if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 0&&j!=b (j + 2) % 2 == 0 (j + 2) % 2 (j + 2) j 2 2 0 j!=b j b {
                            System.out.print(".");
                        } System.out.print(".") System.out.print System.out System System.out "." if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 1 (j + 2) % 2 (j + 2) j 2 2 1 {
                            System.out.println("#");
                            
                        } System.out.println("#") System.out.println System.out System System.out "#" {
                            System.out.println(".");
                        } System.out.println(".") System.out.println System.out System System.out "." if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 0&&j!=b (j + 2) % 2 == 0 (j + 2) % 2 (j + 2) j 2 2 0 j!=b j b {
                            System.out.print("#");
                        } System.out.print("#") System.out.print System.out System System.out "#" if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 1&&j!=b (j + 2) % 2 == 1 (j + 2) % 2 (j + 2) j 2 2 1 j!=b j b {
                            System.out.print(".");
                        } System.out.print(".") System.out.print System.out System System.out "." if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        } (j + 2) % 2 == 0 (j + 2) % 2 (j + 2) j 2 2 0 {
                            System.out.println("#");
                            
                        } System.out.println("#") System.out.println System.out System System.out "#" {
                            System.out.println(".");
                        } System.out.println(".") System.out.println System.out System System.out "." System.out.println("") System.out.println System.out System System.out "" String[] args args public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            if (a == 0 && b == 0) {
                break;
            }
            for (int i = 1; i <= a; i++) {
                for (int j = 1; j <= b; j++) {
                    if ((i + 2) % 2 == 1) {
                        if ((j + 2) % 2 == 1&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 0&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 1){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                    } else if ((j + 2) % 2 == 0&&j!=b) {
                            System.out.print("#");
                        } else if((j + 2) % 2 == 1&&j!=b) {
                            System.out.print(".");
                        }
                        else if((j + 2) % 2 == 0){
                            System.out.println("#");
                            
                        }
                        else{
                            System.out.println(".");
                        }
                }
                
            }
            System.out.println("");
        }
    }
}