1.
| 2.
| 3.
| 4.
|
5.
| 6.
| 7.
| 8.
|
9.
| 10.
| 11.
| 12.
|
13.
| 14.
| 15.
| 16.
|
17.
| 18.
| 19.
| 20.
|
The solutions are here.
Divide each puzzle into 9 regions consisting of exactly 4 squares. There are no intersections where 4 of these regions meet, and dots are located at all the intersections where exactly 3 regions meet. The first puzzle is solved as an example.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
The solutions are here.