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