Level Up - Puzzles: Connect a 4x4 Grid of Dots With 6 Contiguous Lines (Solution)

Before reading this post, you should read my last one which introduces the puzzles better.

A common brain teaser is to connect a 3 by 3 grid of dots with four straight lines without picking up the pencil. After solving a 3x3, try to solve a 4x4, 5x5, etc. I have a proof that all of them have a solution.

Click read more to see the solutions and explanations: