In 3D graphics, two triangles that share a common edge (i.e., two vertices) and 

lie on the same plane can be rendered more efficiently than two separate triangles¹. 

This is because graphics hardware can use structures like **Triangle Strips**,

which only need to store 1 point for each additional triangle after the first¹. 

This makes them very memory efficient and allows them to be sorted and rendered 

extremely fast¹.

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On the other hand, two separate triangles would each need to store all three of 

their vertices, requiring more memory and potentially slowing down the rendering

process.

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However, it's important to note that the performance difference might not be 

noticeable unless you're dealing with a very large number of triangles. Modern 

graphics hardware is highly optimized and capable of rendering millions of 

triangles per frame. So, while using connected triangles can be more efficient, 

the overall impact on performance will depend on the specific circumstances of 

your 3D scene.