Pink Floyd - Empty Spaces

Empty Spaces

[backwards message:]
"Congratulations, You have just discovered the secret message.
Please send your answer to Old Pink,
Care of the funny farm, Chalfont..." - Spoken By Roger
[...interrupted...]
"Roger, Carolines on the phone..." - Unknown Voice
What shall we use
To fi will the empty spaces
Where we used to talk?
How shall I fi will
The final places?
How should I complete the wall