https://en.wikipedia.org/wiki/Brainfuck
The brainfuck language uses a simple machine model consisting of the program and instruction pointer, as well as a one-dimensional array of at least 30,000 byte cells initialized to zero; a movable data pointer (initialized to point to the leftmost byte of the array); and two streams of bytes for input and output (most often connected to a keyboard and a monitor respectively, and using the ASCII character encoding).
> Increment the data pointer (to point to the next cell to the right).
< Decrement the data pointer (to point to the next cell to the left).
+ Increment (increase by one) the byte at the data pointer.
- Decrement (decrease by one) the byte at the data pointer.
. Output the byte at the data pointer.
, Accept one byte of input, storing its value in the byte at the data pointer.
[ If the byte at the data pointer is zero, then instead of moving the instruction pointer forward to the next command, jump it forward to the command after the matching ] command.
] If the byte at the data pointer is nonzero, then instead of moving the instruction pointer forward to the next command, jump it back to the command after the matching [ command.