STRUCTURES
ARTIFICIAL
RESISTANT
NATURAL
STABLE
K
U
U
K
S
E
O
L
O
M
A
S
W
L
A
Q
T
F
L
U
V
X
G
W
S
M
R
Q
A
V
A
F
P
E
N
M
E
Q
T
L
B
E
R
K
B
A
F
Z
R
A
I
N
L
R
U
A
Z
O
A
K
U
X
F
G
E
D
T
R
X
I
F
X
T
I
I
O
O
W
A
F
E
U
O
A
C
U
C
E
U
P
N
O
A
I
R
Q
U
U
I
K
C
Y
A
U
R
B
W
Y
R
I
A
B
J
I
K
A
L
W
B
W
T
I
L
F
P
Q
K
O
J
U
S
I
S
Q
R
E
S
I
S
T
A
N
T
T
