<s>
The	O
MUD	B-Application
trees	I-Application
below	O
depict	O
hierarchies	O
of	O
derivation	O
among	O
MUD	B-Application
codebases	B-General_Concept
.	O
</s>
<s>
Dotted	O
boxes	O
indicate	O
that	O
the	O
codebase	B-General_Concept
is	O
outside	O
the	O
family	O
depicted	O
.	O
</s>
<s>
Note	O
that	O
codebases	B-General_Concept
are	O
different	O
from	O
individual	O
servers	O
,	O
in	O
the	O
same	O
way	O
that	O
a	O
biological	O
family/genus/species	O
is	O
different	O
from	O
a	O
specific	O
bird	O
at	O
a	O
zoo	O
or	O
fossil	O
imprint	O
in	O
a	O
museum	O
.	O
</s>
<s>
Some	O
of	O
the	O
codebases	B-General_Concept
below	O
are	O
incredibly	O
popular	O
,	O
with	O
many	O
servers	O
based	O
on	O
them	O
;	O
other	O
codebases	B-General_Concept
may	O
only	O
be	O
found	O
on	O
archive	O
sites	O
,	O
making	O
them	O
available	O
but	O
effectively	O
extinct	O
.	O
</s>
<s>
For	O
a	O
list	O
of	O
specific	O
servers	O
using	O
some	O
of	O
these	O
codebases	B-General_Concept
,	O
see	O
the	O
Chronology	B-Protocol
of	I-Protocol
MUDs	I-Protocol
article	O
.	O
</s>
