Creating a symmetric matrix from a single column vector

How do I create a symmetric matrix from a given column vector, e.g. [1 2 3; 2 1 2; 3 2 1] from [1; 2; 3]?

I have a 84x1 column vector of data so need a quick method.

Answer 1

[Star Strider]

That same example is in the documentation for the toeplitz function.