Here is Roger Waters singing "Brain Damage" in a studio for the Making of the Dark Side of the Moon documentary.

The lunatic is on the grass
Remembering games
And daisy chains and laughs
Got to keep the loonies on the path

The lunatic is in the hall

The lunatics are in my hall
The paper holds their folded faces to the floor
And every day the paper boy brings more

And if the dam breaks open many years too soon

And if there is no room upon the hill
And if your head explodes with dark forebodings too
I'll see you on the dark side of the moon

The lunatic is in my head

You raise the blade
You make the change
And you rearrange me 'till I'm sane
You lock the door
And throw away the key
And there`s someone in my head, but it's not me

And if the cloud bursts thunder in your ear

You shout and no one seems to hear
And if the band you're in starts playing different tunes
I'll see you on the dark side of the moon

Roger Waters explains in that documentary that a "Do not step on the grass" sign inspired him to write this song. Society lays down the rules - some explicit, and some implicit which comprise an overall structure in which to operate. But often the rules make no sense to some. And to others, those who oppose them make no sense - they are criminals or lunatics. Interestingly, the bauls of Bangla also commonly sang describing themselves as "pagol" or "pagla" (lunatics, mad men). It does seem that they derived that title for themselves from what people around them were saying about them. They were on the grass.
জাত গেল জাত গেল বলে
একি আজব কারখানা
সত্য কাজে কেউ নয় রাজী
সবই দেখি তানা না না।।