Minecraft wiki entry for Zero-ticking, associated text: One method of 0-tick chaining is to utilize the fact that tileticks such as repeaters and comparators will process in a tick before block events such as piston extensions and retractions. In the shown example, when the input is powered, the quartz block will be 0-ticked by both pistons causing it to instantly move two blocks, ending up above the diamond block. The 0-tick generator to the right makes use of tileticks and will activate before the 0-tick generator on the left, which uses block events. This method of chaining is very compact, but it comes at a downside that this method can only be used once per chain.