-3
-2
-1
0
1
2
3
-5
0
5
10
15
s1 (a=1.02)
-3
-2
-1
0
1
2
3
-5
0
5
10
15
20
25
s2 (a=1.99)
-3
-2
-1
0
1
2
3
0
10
20
30
s3 (a=3.03)
-3
-2
-1
0
1
2
3
0
10
20
30
40
s4 (a=3.96)