import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class Main{
    public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Arrays; Arrays java.util import java.util.List; List java.util import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.Comparator; Comparator java.util public class Main{
    public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    }
} Main public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    } main {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    } try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	} Exception e {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	} System.out.println(e.getMessage()) System.out.println System.out System System.out e.getMessage() e.getMessage e System.out.println(Arrays.toString(e.getStackTrace())) System.out.println System.out System System.out Arrays.toString(e.getStackTrace()) Arrays.toString Arrays e.getStackTrace() e.getStackTrace e System.exit(0) System.exit System 0 {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) List<String> lines = new ArrayList<String>(); lines new ArrayList<String>() for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    } String line = br.readLine(); String line = br.readLine(); line br.readLine() br.readLine br line != null line null line = br.readLine() line = br.readLine() line br.readLine() br.readLine br {
		lines.add(line);
	    } {
		lines.add(line);
	    } lines.add(line) lines.add lines line br.close() br.close br for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    } Integer i = 0; Integer i = 0; i 0 i < lines.size() i lines.size() lines.size lines i++ i++ i {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    } {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    } String[] splits = lines.get(i).split(" "); splits lines.get(i).split(" ") lines.get(i).split lines.get(i) lines.get lines i " " Integer H = Integer.parseInt(splits[0]); H Integer.parseInt(splits[0]) Integer.parseInt Integer splits[0] splits 0 Integer W = Integer.parseInt(splits[1]); W Integer.parseInt(splits[1]) Integer.parseInt Integer splits[1] splits 1 if (H==0&&W==0) {
		    System.exit(0);
		} H==0&&W==0 H==0 H 0 W==0 W 0 {
		    System.exit(0);
		} System.exit(0) System.exit System 0 for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		} int h = 0; int h = 0; h 0 h < H h H h++ h++ h {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		} {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		} char[] chars = new char[W]; chars new char[W] W Arrays.fill(chars, '#') Arrays.fill Arrays chars '#' StringBuilder sb = new StringBuilder(new String(chars)); sb new StringBuilder(new String(chars)) for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    } int j=0; int j=0; j 0 j<chars.length j chars.length chars chars.length j++ j++ j {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    } {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    } if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			} h%2==0 && j%2==1 h%2==0 h%2 h 2 0 j%2==1 j%2 j 2 1 {
			    sb.setCharAt(j,'.');
			} sb.setCharAt(j,'.') sb.setCharAt sb j '.' if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			} h%2==1 && j%2==0 h%2==1 h%2 h 2 1 j%2==0 j%2 j 2 0 {
			    sb.setCharAt(j,'.');
			} sb.setCharAt(j,'.') sb.setCharAt sb j '.' System.out.println(sb.toString()) System.out.println System.out System System.out sb.toString() sb.toString sb System.out.println("") System.out.println System.out System System.out "" System.exit(0) System.exit System 0 String[] args args public class Main{
    public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    }
} public class Main{
    public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class Main{
    public static void main(String[] args) {
	try {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    List<String> lines = new ArrayList<String>();

	    for (String line = br.readLine(); line != null; line = br.readLine()) {
		lines.add(line);
	    }
	    //lines.add("3 4");
	    //lines.add("5 6");
	    //lines.add("3 3");
	    //lines.add("2 2");
	    //lines.add("1 1");
	    //lines.add("0 0");
	    br.close();

	    for (Integer i = 0; i < lines.size(); i++) {
		String[] splits = lines.get(i).split(" ");
		Integer H = Integer.parseInt(splits[0]);
		Integer W = Integer.parseInt(splits[1]);

		if (H==0&&W==0) {
		    System.exit(0);
		}

		for (int h = 0; h < H; h++) {
		    char[] chars = new char[W];
		    Arrays.fill(chars, '#');

		    StringBuilder sb = new StringBuilder(new String(chars));
		    for (int j=0; j<chars.length;j++) {
			if (h%2==0 && j%2==1) {
			    sb.setCharAt(j,'.');
			} else if (h%2==1 && j%2==0) {
			    sb.setCharAt(j,'.');
			}
		    }

		    System.out.println(sb.toString());
		}

		System.out.println("");
	    }
	    System.exit(0);

	} catch (Exception e) {
	    System.out.println(e.getMessage());
	    System.out.println(Arrays.toString(e.getStackTrace()));
	    System.exit(0);
	}
    }
}