Why do QR codes have 3 squares?

Related questions

1. How does QR code work?
2. Can barcode scanners read QR codes?
3. What is a QR code on a phone?
4. How are QR codes used?
5. Can QR codes expire?
6. What information is stored on a barcode?
7. How do dynamic QR codes work?
8. Are QR codes secure?
9. Can you change where a QR code goes?
10. Can QR codes be dangerous?

Tags

1. #corrections
2. #quickly
3. #alignment
4. #detects
5. #square
6. #small
7. #allow
8. #image
9. #reader
10. #allows
11. #orient
12. #order
13. #called
14. #identify
15. #markers
16. #boxes
17. #distortion
18. #curvature
19. #position
20. #squares
21. #needed