Help me to understand PROGMEM prog_uchar how it's works?

Hello team,

Please help me to understand PROGMEM prog_uchar how it’s works?
I wish to create more visual characters on 8x8 matrics but I don’t get this strange encoding:
For characters # it’s goes as: 5, 8, B00010100, B00111110, B00010100, B00111110, B00010100, // #

It’s not Decimal and not hex, what is this?

#include <MaxMatrix.h>
#include <avr/pgmspace.h>
 
 
PROGMEM prog_uchar CH[] = {
3, 8, B00000000, B00000000, B00000000, B00000000, B00000000, // space
1, 8, B01011111, B00000000, B00000000, B00000000, B00000000, // !
3, 8, B00000011, B00000000, B00000011, B00000000, B00000000, // "
5, 8, B00010100, B00111110, B00010100, B00111110, B00010100, // #
4, 8, B00100100, B01101010, B00101011, B00010010, B00000000, // $
...

Source:

It's binary.

B000100 is just an arduinoism to define binary numbers.

But I don't get how this B00000000, B00000000, B00000000, B00000000, B00000000 define the matrix 8x8 ?

As binary, it's supposed to represent 8x8 as: {B00000000, B00000000, B00000000, B00000000, B00000000, B00000000, B00000000, B00000000}

Source: http://blog.riyas.org/2013/12/online-led-matrix-font-generator-with.html

But in this case it's kind of 5 rows: B00000000, B00000000, B00000000, B00000000, B00000000

Such a strange representation of 8x8 led matrix screen. :(