Hi, I'm William Lidwell and this is
Zb#Universal Principles of Design.
In this movie KISS; Keep It Simple Stupid.
The acronym KISS stands for
Keep It Simple Stupid.
But more politically correct variations
are often used like Keep It Short & Simple,
and Keep It Simple Silly.
The original less politic phrasing of the
principle Keep It Simple Stupid
was popularized by Kelly Johnson the
J8legendary lead engineer of the Lockheed Skunkworks.
If you've never heard of Kelly Johnson
he led the design of advanced aircraft such
as the P-38 Lightening, F-104 Starfighter
and the SR-71 Blackbird.
A%He is considered one of the great
aircraft designers and R&D leaders
of the 20th century.
Johnson designed aircraft for war which
meant planes had to perform reliably
and they had to be easy to fix in rough,
stressful field conditions.
And one of the most powerful principles
he employed to do this was KISS.
The KISS principle asserts that simple systems
work better than complex systems. !
Accordingly, simplicity should be a key goal in design. "
~1'Simplicity means minimal parts with #
minimal interactions between those parts. $
So given the chose between two functionally %
C64equivalent systems, car engines, or algorithms, &
or work flows, the ones with fewer parts '
and interactions between parts will be (
will perform more reliably and will be easier *
to troubleshoot and maintain. +
d@+Now, in practice it's important to note ,
that innovative designs rarely start off simple. -
The process iteration and prototyping is messy .
and designs invariably accure inessential /
elements and interactions as they are developed. 0
The KISS principle most often comes into play 1
once a design nears a working prototype. 2
M;At this point KISS is a good tool to prove complexity. 3
Iterations become increasingly subtractive. 4
Good designers ask, what can be removed 5
NrS without hurting performance? 6
T*And they keep removing and simplifying 7
and applying KISS until they can't simplify any further. 8
Until subtracting something hurts 9
a performance requirement. :
That's when they know to stop. ;
],On of the greatest examples of this type <
of KISS process applied is the AK-47 Assault Rifle. =
Invented by Mikhail Kalashnikov. >
The AK-47 began as a kind of Frankenstein rifle. ?
d2Borrowing from a variety of existing designs. @
But through this process of iterative subtraction A
it was simplified to having only eight moving parts. B
It is arguably the most successful firearm in history C
m7with an estimated 70 to 100 million of the weapons D
in circulation. E
p,Tragically these very qualities have led F
the rifle to become the preferred weapon of G
s.criminals and terror its across the world. H
A year before he died Kalashnikov said, I
It is painful for me to see when J
Aw8criminal elements of all kinds fire from my weapon. K
AI created this weapon primarily to safeguard our fatherland. L
H{8This serves as a healthy reminder to all designers. M
The KISS principle helps give us N
quality and reliability but not wisdom. O
So, wether you use KISS to speed up P
production processes, increase the reliability Q
of mechanisms, or increase the clarity and R
maintainability of software remember S
smart design requires that you T