Editing K-map (section)

=== Okay, so how does it look like? ===
Usually you start with a truth table with 4 inputs and an output column with values that are either {{Off}} or {{On}}. In this example the output values doesn't matter (yet), but notice that I gave them numbers from 0 to 15 that matches their corresponding input bit pattern.

[[File:4bit_TruthTable_decimal_output.png]]

A Karnaugh map is a truth table, where each bit combination is represented in 2D form. 
So the outputs are not a straight line like above, but like a square:

[[File:KMap_undefined_output.png]]

As a careful observer, you may have noticed something strange: The input combinations are not numbered 0-1-2-3 (in binary), but '''0-1-3-2'''! 

<blockquote>Why though?!</blockquote>

The answer: We make sure, that '''only 1 bit changes in each step'''. So if we would go 0-1-2-3, then the step from 1 to 2 in binary would be 01 to 10. '''Both''' bits would change, but we only want 1 bit to change at max. This is why we swap the order of the inputs, but make sure, that we still have all possible combinations available.

<blockquote>BUT WHYYY?!</blockquote>
Yes, yes... later...

Changing the order of the input also changes the order in which we fill in the outputs. Going from left to right, skipping the third column and going from top to bottom, skipping the third row. The white numbers are the order in which you plug in the output values.

[[File:KMap_undefined_output_graycode.png]]
[[File:KMap_decimal_output_graycode.png]]