Bijan Finds Rostam's Ring in the Pit

From C2.23, Bijan Learns Rostam Is Coming. It illustrates C2.23.12–22:

C2.23.12
Bijan unfolded all the wholesome bread,With hope at times, at times with fear and dread.
C2.23.13
He reached to eat and found the hidden ringAmid the food that she had come to bring.
C2.23.14
He read the name and marveled at the sight;He laughed aloud in wonder and delight.
C2.23.15
A turquoise seal bore Rostam’s name; each lineWas cut with iron, like a hair so fine.
C2.23.16
He saw the fruit of faithfulness appear,And knew the key to grief at last was here.
C2.23.17
He laughed in royal gladness from the pit,Until Manijeh heard, amazed by it.
C2.23.18
She marveled at his laughter from that gloom,Where chains and darkness wrapped him like a tomb.
C2.23.19
She spoke a proverb, puzzled by his glee:“A madman laughs at his own acts,” said she.
C2.23.20
She stood bewildered by the sound below:“O fortunate one, why does your laughter flow?
C2.23.21
How can your lips spread open with delight,When night is day to you, and day is night?
C2.23.22
What mystery is this? Reveal it now.Does better fortune show a brighter brow?”