Can you solve the Six-Box Puzzle?

When I first came across this puzzle, it seemed impossible at first glance. After a many attempts I stumbled on the "simple" solution. This brain teaser delivers a delightful "aha!" moment when you finally crack it.

The challenge: connect the three pairs of numbered boxes within a rectangular boundary without any lines intersecting.

The puzzle's rules:

  1. Connect the two boxes labeled 1 with a line
  2. Connect the two boxes labeled 2 with another line
  3. Connect the two boxes labeled 3 with a third line
  4. The lines cannot intersect each other
  5. The lines must remain within the rectangular boundary
  6. The lines do not have to be straight

If you give up, there's no shame! Here's the solution.