Empty Spaces - Band Demo Lyrics

[(Spoken backwards) Congratulations, You have just discovered the secret message. Please send your answer to 'Old Pink', Care of the funny farm, Chalfont...(interruption) Roger, Caroline's on the phone...]

What shall we use to fill the emptyPink Floyd - Empty Spaces - Band Demo - http://motolyrics.com/pink-floyd/empty-spaces-band-demo-lyrics.html
Spaces where we used to talk
How shall I fill the final places
How should I complete the wall