For a two-belt balancer you could notate it like this: This is actually comparable to doing a simple number average. When building a multi-belt balancer you need to keep the basic definition in mind and make sure that your inputs are averaged across all of your outputs. What does this mean when building a multi-belt balancer? This may seem simplistic and obvious but it lets us make some conclusions about larger belt balancers down the road. Now that we understand the humble Splitter, we have enough to give a simple defintion for a multi-belt balancer.ДЄ multi-belt balancer will take any number of inputs and divide the items from the inputs equally among any number of outputs. For purposes of simplicity, let's just assume that we have only one item on our belts and take it as given that the Splitter will always give you an equal number of items on each of its 2 output belts.) Formal definition The logic that a Splitter uses to decide which output something will go to is fairly complex, though, and gets even more so when you have more than one type of item on a belt. Any item on the left lane will always stay in the left lane, no metter how many splitters it goes through. The Splitter, on its own, will never mix the contents of the left lane of a belt with the right lane of a belt. (Note that this post treats belts as a single unit even though every belt has two lanes within it which are distinct and separate. We'll touch more on this later, but for now let's just assume that all belts are flowing freely. Multi-belt balancers at their simplest form take the same number of inputs as they have outputs and don't worry about backups or blocked outputs. This is the simplest form of a multi-belt balancer, the one which Factorio has given us and also the basic building block of any larger multi-belt balancer.

So a better name for the Splitter might be a Two-Belt Balancer.

Factorio lane balancer