2Way and 3Way Link-Building

What is 2Way and 3Way Link-Building?

Which is best? 2Way or 3Way Link-Building,

I would like to know SEO point of vision.

Please help me,

Thanks in Advance.

both are good....there is no specific instructions for any ...you get a link to your website in both .

Two way link building: where two websites mutually agree to link each other.
Three way link building: Where 3 website connected each other with links.