How can QR code store so much data?

Question

Quick googling result that QR code can hold nearly 3kb (8 bit) data. But isn\'t it just using black/white dots to represent bits? If so there\'s no way that there\'s over 20,000

Answer 1

Denso Wave says that the QR bar code can be as large as 177 by 177, allowing for 31,329 dots. That is enough space for about 3kB, even allowing for position, alignment, timing, version, and formatting information.