1
STRUCTURES
2
ARTIFICIAL
3
RESISTANT
4
NATURAL
5
STABLE
O
J
U
E
S
I
Z
T
E
U
D
Q
T
I
A
G
T
U
L
I
I
G
V
W
S
S
R
A
A
A
A
U
Q
E
H
R
E
C
T
W
B
X
R
F
U
O
S
V
R
Z
I
M
L
U
U
E
T
I
C
W
U
O
F
J
E
N
T
E
N
Q
I
P
T
O
I
H
V
A
A
O
Z
C
H
L
C
A
C
I
M
V
N
Q
H
V
S
Y
U
W
I
U
F
M
V
E
G
X
U
U
R
V
A
M
L
Y
D
U
V
Q
M
I
T
E
L
I
E
A
G
O
I
Y
A
H
S
O
R
E
S
I
S
T
A
N
T
Y