Merging different position (length) lines ??

As shown above, when lines 1 and 2 are different in length and position, they merge.

Do you have any mathematical methods or other methods? I think that's what happens when we merge.

Can you do this in the matlab?

Could you write me a matlab code that combines two lines with different positions?

My English is not good. I'm sorry.

[darova]

The question is unclear. How merging works?