# beans computing
non-electronic {digital systems} based on manipulating beans according to simple logical rules.
inspired by {the beans computer}, but going at a lower level.
the {computadora de papel} is also related as a beans-based, "higher level" computer.
# projects and prototypes
{norpet} is a proof-of-concept for ideas we have about beans computing in an 8x8 grid or board.
# truth tables
we have only two classes of beans: black (1), and non-black (0).
these tables correspond to the NOT and NOR logical operations.
they show their possible inputs at their left, and their corresponding outputs to the right.
=> ./img/foto_beans-computing_truth-tables.png photo of the NOT and NOR truth tables, composed of beans in a greenish surface
## NOT
NOT: the output is the opposite of the input. (table at the top left)
+
+ input | output |
+ 0 | 1 |
+ 1 | 0 |
+
& * input: 0, output: 1
& * input: 1, output: 0
## NOR
NOR: the output is black only when none of the inputs are black. in any other case, the output is non-black. (table at the center) {nor}
+
+ inputs | output |
+ 00 | 1 |
+ 01 | 0 |
+ 10 | 0 |
+ 11 | 0 |
+
& * inputs: 00, output: 1
& * inputs: 01, output: 0
& * inputs: 10, output: 0
& * inputs: 11, output: 0
if you look closely you'll see that NOT can be defined the same way as NOR.
by combining multiple instances of this logic operation, we could build any possible digital behavior.