With the activation of this puzzle in the escape room "knockers" begin to knock in a certain pre-set rhythm."Knocks" can be installed not only in the cabinet, for example, if they are installed on the shelves, you can drop objects from them.
If you have installed it in the cabinet, the module can be used to get a hint. For example, a knock occurs only in those places in which certain symbols are plotted.
Having found out by what symbols there is a knocking you can get a hint for another puzzle in the room escape. Or if you set them in a square and set the desired sequence of knocking, you can eventually get a hint of this type: 3 left, 1 top, 4 bottom, 2 right. The options are limited only by your imagination.