Control the flow of pattern

I have made a gradient pattern from the triangular panels of lunchbox on a surface. But the panels are getting stretched towards the edge of the surface. How can I avoid that?

you could do something like this, making the panels smaller when the surface gets narrower: (18.1 KB)

Thank you for the suggestion. Actually, I am interested in maintaining a constant shape of the triangular cells irrespective of the shape of the surface it’s on.
I have added a reference photo of a pattern flowing on a surface but maintaining its shape.