Two persons, two different worlds(masses at lower left-middle, upper right). They are different, but they are friends. The friendship is built on two things-bridges: Solidarity and Peace of Mind. Solidarity is when people have something in common: interests, purposes, enemies, etc. You get peace of mind when your friend is around and you can depend on him. You can relax and move part of the weight of the burden that presses onto your mind to your friend.The friend gives you some kind of mental relief.So, we see here a friendship in making.