From Minecraft Wiki
|This page contains content on features that may be included in a future update.
These features were presented by Mojang, but are not confirmed yet.
Configurations of such a device have existed in Minecraft due to a glitch labelled as a "feature", allowing circuits to detect block updates. This block would simplify the process into one block.
|24 November, 2012||Jeb stated that he may add a BUD switch.|