H,W,X = map(int,input().split())
h = (H+1)//2
w = (W+1)//2

if not 2*h+2*w-4<=X<=2*h*w-2:
    exit(print(-1))
diff = X - (2*h+2*w-4)
if diff%4!=0:
    exit(print(-1))

if w%2==1:
    ans = [["." for j in range(W)] for i in range(H)]
    pos = (0,0)
    rest_dist = X
    ans[0][0] = "T"
    while pos!=(H-1,W-1):
        x,y = pos
        if rest_dist != (H-1-x) + (W-1-y):
            if x==0:
                if (y//2)%2==1:
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                else:
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)
            elif x==H-1:
                if (y//2)%2==0:
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                else:
                    ans[x-1][y] = "T"
                    ans[x-2][y] = "T"
                    pos = (x-2,y)
            elif (y//2)%2==0:
                ans[x+1][y] = "T"
                ans[x+2][y] = "T"
                pos = (x+2,y)
            else:
                ans[x-1][y] = "T"
                ans[x-2][y] = "T"
                pos = (x-2,y)
            rest_dist -= 2
        else:
            while pos[1]!=W-1:
                x,y = pos
                ans[x][y+1] = "T"
                ans[x][y+2] = "T"
                pos = (x,y+2)
            while pos[0]!=H-1:
                x,y = pos
                ans[x+1][y] = "T"
                ans[x+2][y] = "T"
                pos = (x+2,y)


    stack = [(i,j) for i in range(H) for j in range(W) if ans[i][j]=="T" and i%2==0 and j%2==0]

    while stack:
        x,y = stack.pop()
        if x+2<=H-1 and ans[x+2][y]!="T":
            ans[x+2][y] = "T"
            ans[x+1][y] = "T"
            stack.append((x+2,y))
        if 2<=x and ans[x-2][y]!="T":
            ans[x-2][y] = "T"
            ans[x-1][y] = "T"
            stack.append((x-2,y))
        if y+2<=W-1 and ans[x][y+2]!="T":
            ans[x][y+2] = "T"
            ans[x][y+1] = "T"
            stack.append((x,y+2))
        if 2<=y and ans[x][y-2]!="T":
            ans[x][y-2] = "T"
            ans[x][y-1] = "T"
            stack.append((x,y-2))
    for i in range(H):
        for j in range(W):
            if ans[i][j]=="T":
                ans[i][j]="."
            else:
                ans[i][j]="#"
        print("".join(ans[i]))
elif h%2==1:
    H,W = W,H
    h,w = w,h
    ans = [["." for j in range(W)] for i in range(H)]
    pos = (0,0)
    rest_dist = X
    ans[0][0] = "T"
    while pos!=(H-1,W-1):
        x,y = pos
        if rest_dist != (H-1-x) + (W-1-y):
            if x==0:
                if (y//2)%2==1:
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                else:
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)
            elif x==H-1:
                if (y//2)%2==0:
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                else:
                    ans[x-1][y] = "T"
                    ans[x-2][y] = "T"
                    pos = (x-2,y)
            elif (y//2)%2==0:
                ans[x+1][y] = "T"
                ans[x+2][y] = "T"
                pos = (x+2,y)
            else:
                ans[x-1][y] = "T"
                ans[x-2][y] = "T"
                pos = (x-2,y)
            rest_dist -= 2
        else:
            while pos[1]!=W-1:
                x,y = pos
                ans[x][y+1] = "T"
                ans[x][y+2] = "T"
                pos = (x,y+2)
            while pos[0]!=H-1:
                x,y = pos
                ans[x+1][y] = "T"
                ans[x+2][y] = "T"
                pos = (x+2,y)


    stack = [(i,j) for i in range(H) for j in range(W) if ans[i][j]=="T" and i%2==0 and j%2==0]

    while stack:
        x,y = stack.pop()
        if x+2<=H-1 and ans[x+2][y]!="T":
            ans[x+2][y] = "T"
            ans[x+1][y] = "T"
            stack.append((x+2,y))
        if 2<=x and ans[x-2][y]!="T":
            ans[x-2][y] = "T"
            ans[x-1][y] = "T"
            stack.append((x-2,y))
        if y+2<=W-1 and ans[x][y+2]!="T":
            ans[x][y+2] = "T"
            ans[x][y+1] = "T"
            stack.append((x,y+2))
        if 2<=y and ans[x][y-2]!="T":
            ans[x][y-2] = "T"
            ans[x][y-1] = "T"
            stack.append((x,y-2))
    for i in range(H):
        for j in range(W):
            if ans[i][j]=="T":
                ans[i][j]="."
            else:
                ans[i][j]="#"

    rev = [[ans[j][i] for j in range(H)] for i in range(W)]
    for i in range(W):
        print("".join(rev[i]))
else:
    ans = [["." for j in range(W)] for i in range(H)]
    pos = (0,0)
    rest_dist = X
    ans[0][0] = "T"
    while pos!=(H-1,W-1):
        x,y = pos
        if rest_dist != (H-1-x) + (W-1-y):
            if y==W-3:
                if (x//2)%2==0:
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                else:
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)
            elif y==W-1:
                if (x//2)%2==0:
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)
                else:
                    ans[x][y-1] = "T"
                    ans[x][y-2] = "T"
                    pos = (x,y-2)
            else:
                if x==0:
                    if (y//2)%2==1:
                        ans[x][y+1] = "T"
                        ans[x][y+2] = "T"
                        pos = (x,y+2)
                    else:
                        ans[x+1][y] = "T"
                        ans[x+2][y] = "T"
                        pos = (x+2,y)
                elif x==H-1:
                    if (y//2)%2==0:
                        ans[x][y+1] = "T"
                        ans[x][y+2] = "T"
                        pos = (x,y+2)
                    else:
                        ans[x-1][y] = "T"
                        ans[x-2][y] = "T"
                        pos = (x-2,y)
                elif (y//2)%2==0:
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)
                else:
                    ans[x-1][y] = "T"
                    ans[x-2][y] = "T"
                    pos = (x-2,y)
            rest_dist -= 2
        else:
            if y==W-3:
                if (x//2)%2==0:
                    while pos[0]!=H-1:
                        x,y = pos
                        ans[x+1][y] = "T"
                        ans[x+2][y] = "T"
                        pos = (x+2,y)
                    while pos[1]!=W-1:
                        x,y = pos
                        ans[x][y+1] = "T"
                        ans[x][y+2] = "T"
                        pos = (x,y+2)
                else:
                    while pos[0]!=H-1:
                        x,y = pos
                        ans[x+1][y] = "T"
                        ans[x+2][y] = "T"
                        pos = (x+2,y)
                    while pos[1]!=W-1:
                        x,y = pos
                        ans[x][y+1] = "T"
                        ans[x][y+2] = "T"
                        pos = (x,y+2)
            elif y==W-1:
                while pos[1]!=W-1:
                    x,y = pos
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
            else:
                while pos[1]!=W-1:
                    x,y = pos
                    ans[x][y+1] = "T"
                    ans[x][y+2] = "T"
                    pos = (x,y+2)
                while pos[0]!=H-1:
                    x,y = pos
                    ans[x+1][y] = "T"
                    ans[x+2][y] = "T"
                    pos = (x+2,y)

    stack = [(i,j) for i in range(H) for j in range(W) if ans[i][j]=="T" and i%2==0 and j%2==0]

    while stack:
        x,y = stack.pop()
        if x+2<=H-1 and ans[x+2][y]!="T":
            ans[x+2][y] = "T"
            ans[x+1][y] = "T"
            stack.append((x+2,y))
        if 2<=x and ans[x-2][y]!="T":
            ans[x-2][y] = "T"
            ans[x-1][y] = "T"
            stack.append((x-2,y))
        if y+2<=W-1 and ans[x][y+2]!="T":
            ans[x][y+2] = "T"
            ans[x][y+1] = "T"
            stack.append((x,y+2))
        if 2<=y and ans[x][y-2]!="T":
            ans[x][y-2] = "T"
            ans[x][y-1] = "T"
            stack.append((x,y-2))
    for i in range(H):
        for j in range(W):
            if ans[i][j]=="T":
                ans[i][j]="."
            else:
                ans[i][j]="#"
        print("".join(ans[i]))