A fork in the flow
In Terraria, water is displayed as liquid inside square tiles, but its movement is governed by game rules rather than by a continuously measured volume. In a V-shaped channel, a falling stream can reach the bottom and spread into two branches. Under the conditions that produce this effect, the game fills both branches as though each received a full block of water—even though only one falling block fed the split.
That is why the setup can appear to make water from nothing. The liquid is not being physically divided into two smaller portions; the game’s update process leaves a full amount in each destination. The result is a duplication effect, not a realistic consequence of water flowing through a fork.
Why the shape matters
The V gives the falling water two neighboring paths to occupy. As the game updates the liquid tiles, each side can be filled independently, instead of the incoming water being apportioned between them. The important part is the arrangement: a falling block meets a split where both branches can accept water.
For players, the practical implication is simple: a compact V-shaped build can produce more water downstream than it seems to contain upstream. It turns a familiar piece of fluid behavior into a quirk of Terraria’s tile-based simulation—and makes the game’s rules, rather than conservation of volume, the deciding factor.
