At first it's just a tiny scratch
But in time it grows deeper
Into a big, solid crack
And in time it grows deeper
Until finally it breaks apart
And the pieces then are many
And sometimes not reunite able

But sometimes with time
If the crack wasn't too deep
The pieces can be glued back together
If the crack wasn't too deep
But it will still be there inside the glue
And it is more fragile than ever
And the reunited pieces are not one piece

The window is broken
You should buy a new one.