Analysis:
This quatrain by Saadi Shirazi is a stunningly beautiful love poem, filled with vivid imagery and metaphors. Let's break down each line:

Line 1: سرو از قدت اندازهٔ بالا بُردست

"The cypress tree has taken its height from your stature"
Here, Saadi compares the beloved's height and elegance to that of a cypress tree, a symbol of beauty and grace in Persian poetry. The implication is that the cypress tree itself learned how to be tall and graceful by observing the beloved.

Line 2: بحر از دهنت لؤلؤ لالا بُردست

"The sea has taken its pearls from your lips"
This line compares the beloved's words to pearls. The implication is that the beloved's speech is so precious and valuable that even the sea, a vast and bountiful source of treasures, has taken its pearls from them.

Line 3: هرجا که بنفشه‌ای ببینم گویم

"Wherever I see a violet, I say"
The speaker is so enamored with the beloved that they see their beauty reflected everywhere. Here, they associate the beauty of a violet with a hair from the beloved's head.

Line 4: مویی ز سرت باد به صحرا بُردست

"A hair from your head must have been blown into the meadow"
This line continues the imagery from the previous line. The speaker imagines that every beautiful thing they see in nature is somehow connected to the beloved.

Themes explored in the quatrain:

The beauty of the beloved: The beloved is depicted as a source of all beauty and perfection.
The power of nature: Nature is used as a metaphor to describe the beloved's beauty and grace.
The interconnectedness of all things: The speaker suggests that everything in the world is connected to the beloved.

This quatrain is a celebration of love and beauty. It shows how the beloved has become so central to the speaker's life that they see their reflection in everything around them.