From a book (circa 1966) I have that has lost its cover, so unfortunately I can't quote it:

THE INVISIBLE BACKWARDS-FACING GROCER WHO ROSE TO FAME.

Words and Music by Alasdair Clayre.

John (C) Green the grocer lived a (G7) hesitant (C) life,
he (G) kept his mother to (C) feed and pro-(G7)-tect him,
and he (C) would not dare to (G7) look for a (C) wife,
for he (G) dreaded that women would (G7) all re-(C)-ject him.

One (G) Spring as (F) football (G) was changing to (G7) cricket,
and the (G) roar of the (F) traffic was (C) drowned by (G) birds,
as he (C) went to buy his Springtime (G7) season (C) ticket,
at the (G) booking office window he (G7) read these (Am) words:

(G) Don't try to peer through the (F) holes in the glass,
(G) speak at the opaque (G7) space pro-(C)-vided.

He caught his diesel with a thoughtful air
and saw the little schoolgirls dressed in black,
crushed up on the front seat, combing their hair
in the massive shadow of the driver's back.
And he thought; When those girls see my face,
they giggle with a feminine, tinkling sound.
I will buy a sheet of glass with an opaque space
and serve in the shop with my back turned round.

Saying; Don't try to peer throught the holes in the glass,
speak at the opaque space provided.

The very next day the customers saw
the space above the counter taken
by a sheet of glass not there before;
there was no reply when they asked for bacon.
One of the regulars peered wide-eyed
but all she could see was the back of a head.
Then a hand edged out with her bacon tied
and a neatly printed card which read:

Don't try to peer through the holes in the glass,
speak at the opaque space provided.

Allan