Ruler

The Ruler is an accessory that causes a white grid overlay to display over the entire screen, revealing Terraria's tile layout more clearly (ie. the slots each individual block occupies, and where new blocks would fall if placed). This aides intricate construction, as less trial and error is involved in judging distances, symmetry, and achieving a desired block layout.

The Ruler's effect is purely visual and only affects the player who has it equipped.

It can be purchased from the Goblin Tinkerer for.

Note

 * Although the Ruler primarily has no functional effect on the game, it can have any of the usual accessory Modifiers, and so provide added defense or more maximum Mana, for example. It can be Reforged.
 * Players tend to use the Ruler on a temporary basis, and is recommended to be used only when needed, as the grid it displays is not subtle. It can be a distraction that gets in the way during normal gameplay, and may cause dizziness if left for too long.
 * Does not exist on mobile versions. This makes sense, as the grid is there when you build anyway.