Instructions: Click on the lights next to each type of drum, or change the Rhythm Number. (Hint: if you like a rhythm, save the rhythm number - you can come back and re-enter it later.) Also read the explanation below.

## Explanation

There are 4 instruments (HiHat, Snare, Tom and Base). At any point in time any combination of them can be played.

If you write down "1" for Play and "0" for Don't Play, then you could have a combination like HiHat and Tom being "1010", or HiHat and Base being "1001". All four together is "1111".

 This is called "Binary", because there are only two choices (Yes or No) for each digit. A single binary digit is called a "bit". The word binary comes from "Bi-" meaning two. We see "bi-" in words such as "bicycle" (two wheels) or "binocular" (two eyes).

So, at any point in time these are the possible combinations (1=Play, 0=Don't Play):

HiHat
Snare
Tom
Base
Combin-ation
As
Binary
As
Decimal
As Hexa-
decimal
0
0
0
0
0000
0
0
0
0
0
0
1
0001
1
1
1
0
0
1
0
0010
10
2
2
0
0
1
1
0011
11
3
3
0
1
0
0
0100
100
4
4
0
1
0
1
0101
101
5
5
0
1
1
0
0110
110
6
6
0
1
1
1
0111
111
7
7
1
0
0
0
1000
1000
8
8
1
0
0
1
1001
1001
9
9
1
0
1
0
1010
1010
10
A
1
0
1
1
1011
1011
11
B
1
1
0
0
1100
1100
12
C
1
1
0
1
1101
1101
13
D
1
1
1
0
1110
1110
14
E
1
1
1
1
1111
1111
15
F

In the column next to the Binary Numbers are the matching Decimal Numbers and then the Hexadecimal Numbers.

The Hexadecimal numbers are interesting. They look the same as the decimal numbers up to 9, but then there are the letters ("A',"B","C","D","E","F") in place of the decimal numbers 10 to 15.

So a single Hexadecimal digit can show 16 different values instead of the normal 10.

### How does this help?

Well, in this case it means that a Rhythm Code can be written as "90D2C0819082C0A4", instead of "9,0,13,2,12,0,8,1,9,0,8,2,12,0,10,4".

It is a more natural way to show anything that has 16 combinations ... in other words it is "neat".

### Computers

Also, computers love binary (and hexadecimal) because the computer circuits and memory are based on "on/off" (either a signal is there or not).

 For example, the pictures and sound on a DVD are recorded as tiny little holes that can be "read" by a laser. As the DVD spins, the laser detects if there is a hole (or not) at every location. This is turned into a series of "1"s and "0"s that the computer then turns into sound and images.