import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    }
} Main public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    } main {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) StringBuilder strb = new StringBuilder(); strb new StringBuilder() while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        } true {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        } String[] data = br.readLine().split(" "); data br.readLine().split(" ") br.readLine().split br.readLine() br.readLine br " " int h = Integer.parseInt(data[0]); h Integer.parseInt(data[0]) Integer.parseInt Integer data[0] data 0 int w = Integer.parseInt(data[1]); w Integer.parseInt(data[1]) Integer.parseInt Integer data[1] data 1 if (h == 0 && w == 0) {
                break;
            } h == 0 && w == 0 h == 0 h 0 w == 0 w 0 {
                break;
            } break; boolean hFlg = true; hFlg true boolean wFlg = true; wFlg true for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            } int i = 1; int i = 1; i 1 i <= h i h i++ i++ i {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            } {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            } for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                } int j = 1; int j = 1; j 1 j <= w j w j++ j++ j {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                } {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                } if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    } wFlg {
                        strb.append("#");
                    } strb.append("#") strb.append strb "#" {
                        strb.append(".");
                    } strb.append(".") strb.append strb "." wFlg = !wFlg wFlg !wFlg wFlg strb.append("\n") strb.append strb "\n" hFlg = !hFlg hFlg !hFlg hFlg wFlg = hFlg ? true : false wFlg hFlg ? true : false hFlg true false strb.append("\n") strb.append strb "\n" System.out.print(strb) System.out.print System.out System System.out strb String[] args args public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    }
} public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    }
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder strb = new StringBuilder();
        while (true) {
            String[] data = br.readLine().split(" ");
            int h = Integer.parseInt(data[0]);
            int w = Integer.parseInt(data[1]);
            if (h == 0 && w == 0) {
                break;
            }
            boolean hFlg = true;
            boolean wFlg = true;
            for (int i = 1; i <= h; i++) {
                for (int j = 1; j <= w; j++) {
                    if (wFlg) {
                        strb.append("#");
                    } else {
                        strb.append(".");
                    }
                    wFlg = !wFlg;
                }
                strb.append("\n");
                hFlg = !hFlg;
                wFlg = hFlg ? true : false;
            }
            strb.append("\n");
        }
        System.out.print(strb);
    }
}