Analysis:
This quatrain by Saadi Shirazi is a poignant reflection on the passage of time and the impermanence of beauty. Let's break down the lines:

Line 1: آن خال حسن که دیدمی خالی شد

"That beauty spot I saw has vanished,"
This line refers to a specific beauty mark that the speaker found captivating. It's a symbol of youthful beauty and allure.

Line 2: وان لعبت با جمال جمالی شد

"And that playful beauty has become aged."
Here, the speaker laments the loss of youthful beauty, comparing it to a toy that has been worn out with time.

Line 3: چال زنخش که جان درو می‌آسود

"That mole, where my soul found peace,"
The mole is described as a place of solace for the speaker's soul. It was a source of comfort and beauty.

Line 4: تا ریش برآورد سیه چالی شد

"Has become a dark hollow as a beard grew."
This line contrasts the youthful beauty of the mole with the aging process, symbolized by the growth of a beard.

Deeper Meaning:
This quatrain explores themes of:

The impermanence of beauty: Beauty is fleeting and fades with time.
The passage of time: The speaker is mourning the loss of youth and the beauty associated with it.
The melancholy of aging: The quatrain captures the bittersweet nature of aging and the nostalgia for the past.

This quatrain is a meditation on the transience of beauty and the inevitability of aging. It serves as a reminder to cherish the beauty of the moment, knowing that it will eventually pass. The speaker's emotional attachment to the beauty spot and the mole highlights the deep connection we often form with physical attributes, and the sadness we feel when they change or disappear.