Why do lines 1 and 2 create a matrix?

Hi, I'm new to MATLAB. Why does this code create 2-dimensional arrays? I tried it on a Coursera course and it somehow works but I'm a little confused on how line 1 and 2 create a matrix. Thanks!

function [a,b,c,d]=corners(x)
[y,z]=size(x);
a=x(1,1); %top left
b=x(1,end); %top right
c=x(end,1); %bottom left
d=x(end,end); %bottom right
end

Answer 1

[David Fletcher]

The code doesn't create a 2 dimensional array - it is supplied with a 2 dimensional array (argument x) and the function returns the values that are at the corners of that array

function [a,b,c,d]=corners(x)
[y,z]=size(x); %Gets the size of x - values not used in the function so largely serves no purpose
a=x(1,1); %top left value returned 
b=x(1,end); %top right value returned 
c=x(end,1); %bottom left value returned 
d=x(end,end); %bottom right value returned 
end

[Crystal Judd Unson]

Thank you!