Eye of the Ancients

The Eye of the Ancients is a block added by Botania. It can sense animals in a 6 block radius, and will emit a redstone signal when a Redstone Comparator is placed next to the block. The signal's strength can be calculated as $$strength=n+1$$, where $$n$$ is the number of animals present. For example, when there is 1 animal, it will emit a redstone signal with a strength of 2; when there are 2 animals, it will emit a redstone signal with 3 and so on.

When placed, an eye quickly and constantly appears on each of the four side faces.

Trivia

 * This block is one of Vazkii's favorite blocks. The other is the Open Crate.