Minecraft wiki entry for Logic_gates, associated text: One of the simplest and most classic ways of solving the ripple carry problem is to use instant AND gates that use pistons. These adders are simple and fast, but are inconstant because they use pistons. When blocks are accidentally dropped, the entire circuit breaks. Pistons also have timing awkwardness that can be excruciatingly inconvenient when building an advanced circuit that relies heavily on timing.