Ruler

The Ruler is an accessory, which when equipped, shows a white grid overlay making intricate construction easier.

The Ruler can be bought for from the Goblin Tinkerer. (Note that the Ruler's grid effect may quickly become annoying as the grid can get in the way of other items/furniture.)



Trivia
the ruler apears to be 3 cm and a half, however a block in terraria is one inch.