Here is animation by Ian Rust that shows how the pattern approaches GCD as the even values of n increase. https://streamable.com/l7r96 https://streamable.com/l

Here is animation by Ian Rust that shows how the pattern approaches GCD as the even values of n increase. https://streamable.com/l7r96 https://streamable.com/l7r96 Note that for odd values of n the pattern does not resemble GCD.