I realized why they call it a "rib cage".
People tease and make fun of its prisoner,
i.e. these feelings!
And they call it love,
When an intruder,
i.e. another prisoner enters the same cell
i.e. this heart
it somehow becomes an art!
And when they're broken
and they feel, the pieces of their hearts
have driven them apart,
i.e. when both of them think they are now freed...
That's when the real punishment starts! ✓