A simple mod that allows you to place down the Factorio Logo similar to what can be seen in the Gameplay Trailer here https://www.youtube.com/watch?v=KVvXv1Z6EY8 at around 2 minutes in.

My favorite mod updated for Factorio 0.15 and 0.16, original by R3CONN3R.

You can't place belts in between the letters since it is one entity.

Link to the original mod: Factorio Logo