import java.util.Scanner;

/**
 * 
 */

/**
 * @author kawakami
 */
class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner as = new Scanner(System.in);
		
		int H,W;
		int count1=0;
		int count2=0;
		int count3=0;
		
		
		while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		}
		
		

	}

} import java.util.Scanner; Scanner java.util class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner as = new Scanner(System.in);
		
		int H,W;
		int count1=0;
		int count2=0;
		int count3=0;
		
		
		while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		}
		
		

	}

} Main /**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner as = new Scanner(System.in);
		
		int H,W;
		int count1=0;
		int count2=0;
		int count3=0;
		
		
		while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		}
		
		

	} main {
		// TODO Auto-generated method stub
		Scanner as = new Scanner(System.in);
		
		int H,W;
		int count1=0;
		int count2=0;
		int count3=0;
		
		
		while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		}
		
		

	} Scanner as = new Scanner(System.in); as new Scanner(System.in) int H H W; W int count1=0; count1 0 int count2=0; count2 0 int count3=0; count3 0 while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		} true {
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		} H = as.nextInt() H as.nextInt() as.nextInt as W = as.nextInt() W as.nextInt() as.nextInt as if(H==0 && W==0){
				
				break;
				
			} H==0 && W==0 H==0 H 0 W==0 W 0 {
				
				break;
				
			} break; for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			} int i=0; int i=0; i 0 i<H i H i++ i++ i {
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			} {
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			} if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				} i==2*count1 i 2*count1 2 count1 {
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				} for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					} int j=0; int j=0; j 0 j<W j W j++ j++ j {
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					} {
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					} if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						} j==2*count2 j 2*count2 2 count2 {
							
							System.out.print("#");
							
						} System.out.print("#") System.out.print System.out System System.out "#" {
							
							System.out.print(".");
							count2++;
							
						} System.out.print(".") System.out.print System.out System System.out "." count2++ count2 count2=0 count2 0 {
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				} for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					} int j=0; int j=0; j 0 j<W j W j++ j++ j {
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					} {
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					} if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						} j==2*count2 j 2*count2 2 count2 {
							
							System.out.print(".");
							
						} System.out.print(".") System.out.print System.out System System.out "." {
							
							System.out.print("#");
							count2++;
							
						} System.out.print("#") System.out.print System.out System System.out "#" count2++ count2 count2=0 count2 0 count1++ count1 System.out.println() System.out.println System.out System System.out System.out.println() System.out.println System.out System System.out count1=0 count1 0 String[] args args
import java.util.Scanner;

/**
 * 
 */

/**
 * @author kawakami
 */
class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner as = new Scanner(System.in);
		
		int H,W;
		int count1=0;
		int count2=0;
		int count3=0;
		
		
		while(true){
			H = as.nextInt();
			W = as.nextInt();
			
			if(H==0 && W==0){
				
				break;
				
			}
			
			for(int i=0;i<H;i++){
				
				if(i==2*count1){
					
					for(int j=0;j<W;j++){
						
						if(j==2*count2){
							
							System.out.print("#");
							
						}
						
						else{
							
							System.out.print(".");
							count2++;
							
						}
					}
					count2=0;
				}
				
				else{
					
					for(int j=0;j<W;j++){
					
						if(j==2*count2){
							
							System.out.print(".");
							
						}
						
						else{
							
							System.out.print("#");
							count2++;
							
						}
						
					}
					count2=0;
					count1++;
				}
				
				System.out.println();
				
				
			}
			
			System.out.println();
			count1=0;
		}
		
		

	}

}