<s>
In	O
computing	O
,	O
tombstone	B-Application
diagrams	I-Application
(	O
or	O
T-diagrams	B-Application
)	O
consist	O
of	O
a	O
set	O
of	O
“	O
puzzle	O
pieces	O
”	O
representing	O
compilers	B-Language
and	O
other	O
related	O
language	B-Application
processing	I-Application
programs	I-Application
.	O
</s>
<s>
They	O
are	O
used	O
to	O
illustrate	O
and	O
reason	O
about	O
transformations	O
from	O
a	O
source	O
language	O
(	O
left	O
of	O
T	O
)	O
to	O
a	O
target	B-Application
language	I-Application
(	O
right	O
of	O
T	O
)	O
realised	O
in	O
an	O
implementation	O
language	O
(	O
bottom	O
of	O
T	O
)	O
.	O
</s>
<s>
They	O
are	O
most	O
commonly	O
found	O
describing	O
complicated	O
processes	O
for	O
bootstrapping	B-Application
,	O
porting	O
,	O
and	O
self-compiling	O
of	O
compilers	B-Language
,	O
interpreters	O
,	O
and	O
macro-processors	B-Application
.	O
</s>
<s>
T-diagrams	B-Application
were	O
first	O
used	O
for	O
describing	O
bootstrapping	B-Application
and	O
cross-compiling	O
compilers	B-Language
by	O
Harvey	O
Bratman	O
in	O
1961	O
,	O
who	O
reshaped	O
the	O
diagrams	O
originally	O
introduced	O
by	O
Strong	O
et	O
al	O
.	O
</s>
<s>
(	O
1958	O
)	O
to	O
illustrate	O
UNCOL	B-Application
.	O
</s>
<s>
Terry	O
,	O
explained	O
the	O
usage	O
of	O
T-diagrams	B-Application
with	O
further	O
detail	O
.	O
</s>
<s>
T-diagrams	B-Application
are	O
also	O
now	O
used	O
to	O
describe	O
client-server	O
interconnectivity	O
on	O
the	O
World	O
Wide	O
Web	O
.	O
</s>
