v_$datafile vs v$datafile

Please look at the following two statements which Oracle uses to create v$datafile and v_$datafile.

It looks like V$datafile is a synonym of v_$datafile. However, v_$datafile is a view built from selecting v$datafile. This is a recursive definition...... How can this be???????

create public synonym V$DATAFILE
for SYS.V_$DATAFILE;

create or replace view sys.v_$datafile as
select "FILE#","CREATION_CHANGE#","CREATION_TIME","TS#","RFILE#","STATUS","ENABLED","CHECKPOINT_CHANGE#","CHECKPOINT_TIME","UNRECOVERABLE_CHANGE#","UNRECOVERABLE_TIME","LAST_CHANGE#","LAST_TIME","OFFLINE_CHANGE#","ONLINE_CHANGE#","ONLINE_TIME","BYTES","BLOCKS","CREATE_BYTES","BLOCK_SIZE","NAME","PLUGGED_IN"
from v$datafile;

v$datafile is a synonym for v_$datafile which is a view
whose defienition depends on GV$datafile;

Why I see this in v_$datafile's view statement? It looks like the v_$datafile is a view for v$datafile. Right?

create or replace view sys.v_$datafile as
select "FILE#","CREATION_CHANGE#",
"CREATION_TIME","TS#",
"RFILE#","STATUS","ENABLED",
"CHECKPOINT_CHANGE#","CHECKPOINT_TIME",
"UNRECOVERABLE_CHANGE#","UNRECOVERABLE_TIME",
"LAST_CHANGE#","LAST_TIME","OFFLINE_CHANGE#","ONLINE_CHANGE#",
"ONLINE_TIME","BYTES","BLOCKS","CREATE_BYTES","BLOCK_SIZE",
"NAME","PLUGGED_IN"
from v$datafile;