how to draw a spiral illusion

7:34

3:13

6:37

7:16

5:00

5:33

12:25

4:08

3:02

2:45

4:17

6:35

8:44

4:52

5:43

10:58

2:23

4:17

10:11

2:41

2:26

4:21

3:47

4:54

10:04

2:00

7:31

1:29

3:27

13:26

6:53

6:49

4:23

3:16

5:35

1:25

10:00

6:11

14:49

3:57