Gemini on Question 9, Sep 16

I appreciate the request for absolute honesty! Here is the unvarnished truth:

Technically? It is a perfect English haiku.
You absolutely nailed the 5-7-5 syllable structure:

• •cat sits on the mat (5)
• •the mat is un-der the cat (7)
• •a cat and a mat (5)

Artistically? It is not very good.
Here is why: your poem is essentially a logic loop. It gives us the exact same piece of information three times in a row.

• •Line 1: A is on top of B.
• •Line 2: B is beneath A.
• •Line 3: Here are A and B.

It reads less like a poem and more like a mathematical proof, or a page from a Dr. Seuss book.

How to make it better:
Traditionally, a great haiku does two things: it captures a fleeting moment in time, and it creates a "juxtaposition" (putting two contrasting images next to each other to evoke a feeling). It usually involves the senses—what do you see, hear, or feel?

Instead of just stating that the cat and mat exist, try describing how they exist.

Here are a few ways to elevate your exact same concept (a cat on a mat):

Focusing on the senses:
Dust motes in the sun (5)
A curled up ball of orange (7)
Purring on the rug (5)

Focusing on a funny observation:
I bought a nice rug (5)
Covered in white shedding hair (7)
It is his bed now (5)

The Verdict:
If you were trying to pass a 3rd-grade English assignment on syllable counting, you get an A+. If you are trying to write a compelling poem, you need to swap the literal descriptions for sensory imagery!