#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

void gotoxy (int row, int col)
{
    printf("\n\033[%d;%dH", row, col);
}

int main()
{
    const int M=23, N=80;
    const int d=10000;

    system("clear");

    int way = 1;
    int offset = 1;
    while(offset <= N + M) {
        if(way){
            for(int i = 1; (i <= offset); i++) {
                if(i > M || (N - offset + i <= 0)) continue;
                gotoxy(i, N - offset + i);
                printf("*\n");
                usleep(d);
            }
            gotoxy((offset + 1 <= M) ? (offset + 1) : M , (offset + 1 <= M) ? N : N - (offset - M) - 1);
            printf("*\n");
        } else {
            for(int i = offset; (i > 0); i--) {
                if(i > M || (N - offset + i <= 0)) continue;
                gotoxy(i, N - offset + i);
                printf("*\n");
                usleep(d);
            }
            gotoxy((N - offset >= 1) ? 1 : (offset - N + 2), (N - offset >= 1) ? (N - offset) : 1);
            printf("*\n");
        }

        usleep(d);
        way = !way;
        offset += 2;
    }

    putchar('\n');

    return 0;
}