Lyrics:

The postman came on a Monday
And put a letter in the letterbox (echo)
The postman came on a Tuesday
And put a letter and a frog in the letterbox (echo)
The postman came on a Wednesday
And put a letter and a frog and a mouse
In the letterbox (echo)
The postman came on a Thursday
And put a letter and a frog and a mouse
And a spider in the letterbox (echo)
The postman came on a Friday
And put a letter and a frog and a mouse
And a spider and a snail in the letterbox (echo)
The postman never ever came again
He was fired and he was told that he
Was a very silly boy!