<s>
In	O
software	O
design	O
,	O
the	O
look	B-Application
and	I-Application
feel	I-Application
of	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
comprises	O
aspects	O
of	O
its	O
design	O
,	O
including	O
elements	O
such	O
as	O
colors	O
,	O
shapes	O
,	O
layout	O
,	O
and	O
typefaces	O
(	O
the	O
"	O
look	O
"	O
)	O
,	O
as	O
well	O
as	O
the	O
behavior	O
of	O
dynamic	O
elements	O
such	O
as	O
buttons	O
,	O
boxes	O
,	O
and	O
menus	O
(	O
the	O
"	O
feel	O
"	O
)	O
.	O
</s>
<s>
The	O
term	O
can	O
also	O
refer	O
to	O
aspects	O
of	O
a	O
non-graphical	O
user	O
interface	O
(	O
such	O
as	O
a	O
command-line	B-Application
interface	I-Application
)	O
,	O
as	O
well	O
as	O
to	O
aspects	O
of	O
an	O
API	B-General_Concept
–	O
mostly	O
to	O
parts	O
of	O
an	O
API	B-General_Concept
that	O
are	O
not	O
related	O
to	O
its	O
functional	O
properties	O
.	O
</s>
<s>
Look	B-Application
and	I-Application
feel	I-Application
applies	O
to	O
other	O
products	O
.	O
</s>
<s>
Look	B-Application
and	I-Application
feel	I-Application
in	O
operating	B-General_Concept
system	I-General_Concept
user	B-Application
interfaces	I-Application
serves	O
two	O
general	O
purposes	O
.	O
</s>
<s>
and	O
can	O
translate	O
their	O
experience	O
to	O
other	O
products	O
with	O
the	O
same	O
look	B-Application
and	I-Application
feel	I-Application
.	O
</s>
<s>
Contrary	O
to	O
operating	B-General_Concept
system	I-General_Concept
user	B-Application
interfaces	I-Application
,	O
for	O
which	O
look	B-Application
and	I-Application
feel	I-Application
is	O
a	O
part	O
of	O
the	O
product	O
identification	O
,	O
widget	B-Library
toolkits	I-Library
often	O
allow	O
users	O
to	O
specialize	O
their	O
application	B-Application
look	B-Application
and	I-Application
feel	I-Application
,	O
by	O
deriving	O
the	O
default	O
look	B-Application
and	I-Application
feel	I-Application
of	O
the	O
toolkit	O
,	O
or	O
by	O
completely	O
defining	O
their	O
own	O
.	O
</s>
<s>
This	O
specialization	O
can	O
go	O
from	O
skinning	B-Application
(	O
that	O
only	O
deals	O
with	O
the	O
look	O
,	O
or	O
visual	O
appearance	O
of	O
the	O
graphical	O
control	O
elements	O
)	O
to	O
completely	O
specializing	O
the	O
way	O
the	O
user	O
interacts	B-General_Concept
with	I-General_Concept
the	O
software	O
(	O
that	O
is	O
,	O
the	O
feel	O
)	O
.	O
</s>
<s>
The	O
definition	O
of	O
the	O
look	B-Application
and	I-Application
feel	I-Application
to	O
associate	O
with	O
the	O
application	B-Application
is	O
often	O
done	O
at	O
initialization	O
,	O
but	O
some	O
Widget	B-Library
toolkits	I-Library
,	O
such	O
as	O
the	O
Swing	B-Language
widget	B-Library
toolkit	I-Library
that	O
is	O
part	O
of	O
the	O
Java	B-Language
API	B-General_Concept
,	O
allow	O
users	O
to	O
change	O
the	O
look	B-Application
and	I-Application
feel	I-Application
at	O
runtime	O
(	O
see	O
Pluggable	B-Language
look	I-Language
and	I-Language
feel	I-Language
)	O
.	O
</s>
<s>
Some	O
examples	O
of	O
Widget	B-Library
toolkits	I-Library
that	O
support	O
setting	O
a	O
specialized	O
look	B-Application
and	I-Application
feel	I-Application
are	O
:	O
</s>
<s>
XUL	B-Application
(	O
XML	B-Application
User	I-Application
Interface	I-Application
Language	I-Application
)	O
:	O
The	O
look	B-Application
and	I-Application
feel	I-Application
of	O
the	O
user	B-Application
interface	I-Application
can	O
be	O
specialized	O
in	O
a	O
CSS	B-Language
file	O
associated	O
with	O
the	O
XUL	B-Application
definition	O
files	O
.	O
</s>
<s>
Swing	B-Language
supports	O
specializing	O
the	O
look	B-Application
and	I-Application
feel	I-Application
of	O
widgets	O
by	O
deriving	O
from	O
the	O
default	O
,	O
another	O
existing	O
one	O
,	O
creating	O
one	O
from	O
scratch	O
,	O
or	O
,	O
beginning	O
with	O
J2SE	O
5.0	O
,	O
in	O
an	O
XML	B-Protocol
property	O
file	O
called	O
synth	B-Language
(	O
skinnable	B-Application
look	B-Application
and	I-Application
feel	I-Application
)	O
.	O
</s>
<s>
Some	O
companies	O
try	O
to	O
assert	O
copyright	O
of	O
trade	O
dress	O
over	O
their	O
look	B-Application
and	I-Application
feel	I-Application
.	O
</s>
<s>
The	O
Broderbund	O
v	O
.	O
Unison	O
(	O
1986	O
)	O
case	O
was	O
an	O
early	O
software	O
copyright	O
case	O
that	O
attempted	O
to	O
apply	O
U.S.	O
copyright	O
law	O
to	O
the	O
look	B-Application
and	I-Application
feel	I-Application
presented	O
by	O
a	O
software	O
product	O
.	O
</s>
<s>
Apple	O
Computer	O
was	O
notable	O
for	O
its	O
use	O
of	O
the	O
term	O
look	B-Application
and	I-Application
feel	I-Application
in	O
reference	O
to	O
their	O
Mac	B-Application
OS	I-Application
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
firm	O
tried	O
,	O
with	O
some	O
success	O
,	O
to	O
block	O
other	O
software	O
developers	O
from	O
creating	O
software	O
that	O
had	O
a	O
similar	O
look	B-Application
and	I-Application
feel	I-Application
.	O
</s>
<s>
Apple	O
argued	O
that	O
they	O
had	O
a	O
copyright	O
claim	O
on	O
the	O
look	B-Application
and	I-Application
feel	I-Application
of	O
their	O
software	O
,	O
and	O
even	O
went	O
so	O
far	O
as	O
to	O
sue	O
Microsoft	O
,	O
alleging	O
that	O
the	O
Windows	B-Application
operating	I-Application
system	I-Application
was	O
illegally	O
copying	O
their	O
look	B-Application
and	I-Application
feel	I-Application
.	O
</s>
<s>
Although	O
provoking	O
a	O
vehement	O
reaction	O
from	O
some	O
in	O
the	O
software	O
community	O
,	O
and	O
causing	O
Richard	O
Stallman	O
to	O
form	O
the	O
League	B-Application
for	I-Application
Programming	I-Application
Freedom	I-Application
,	O
the	O
expected	O
landmark	O
ruling	O
never	O
happened	O
,	O
as	O
most	O
of	O
the	O
issues	O
were	O
resolved	O
based	O
on	O
a	O
license	O
that	O
Apple	O
had	O
granted	O
Microsoft	O
for	O
Windows	B-Application
1.0	O
.	O
</s>
<s>
The	O
First	O
Circuit	O
Court	O
of	O
Appeals	O
rejected	O
a	O
copyright	O
claim	O
on	O
the	O
feel	O
of	O
a	O
user	B-Application
interface	I-Application
in	O
Lotus	O
v	O
.	O
Borland	O
.	O
</s>
<s>
In	O
2012	O
and	O
2014	O
,	O
Apple	O
Inc	O
.	O
has	O
filed	O
lawsuits	O
against	O
competing	O
manufacturers	O
of	O
smartphones	B-Application
and	O
tablet	B-Device
computers	I-Device
,	O
claiming	O
that	O
those	O
manufacturers	O
copied	O
the	O
look	B-Application
and	I-Application
feel	I-Application
of	O
Apple	O
's	O
popular	O
iPhone	B-Device
and	O
iPad	B-Device
products	O
.	O
</s>
<s>
An	O
API	B-General_Concept
,	O
which	O
is	O
an	O
interface	O
to	O
software	O
which	O
provides	O
some	O
sort	O
of	O
functionality	O
,	O
can	O
also	O
have	O
a	O
certain	O
look	B-Application
and	I-Application
feel	I-Application
.	O
</s>
<s>
Different	O
parts	O
of	O
an	O
API	B-General_Concept
(	O
e.g.	O
</s>
<s>
are	O
part	O
of	O
the	O
syntax	B-Application
of	O
the	O
API	B-General_Concept
)	O
,	O
or	O
implicitly	O
(	O
i.e.	O
</s>
<s>
are	O
part	O
of	O
the	O
semantics	B-Application
of	O
the	O
API	B-General_Concept
)	O
.	O
</s>
