a,b,c,f = input().split()
try:
    f = int(f)
    if f == 0:
        for i in range(int(a)):
            for j in range(int(b)):
                if i == 0 or j == 0 or i == int(a) - 1 or j == int(b) - 1:
                    print(c, end="")
                else:
                    print(" ", end="")
            print()
except:
    for i in range(int(a)):
        for j in range(int(b)):
            print(c, end="")
        print()