How to make a square continuous pattern in AI?

Hello? Have been engaged in clothing printing design before? Let me tell you something.

Everything is designed casually? There's nothing to say about this. The key is how to make it sustainable. Look at the picture, right? Intuition? I'll draw one for you.

Can you cut it off without wearing a mask? Anyway, it's all the same. Okay, are the pictures next to each other complementary? Let's extend it ~