Wall-In at Natural
Construct a row of buildings at the natural expansion choke to constrict or eliminate access to both the natural and main bases.
Rather than a build order, this is a layout strategy that allows you to wall off your natural expansion, allowing for safer (and earlier) expansion and establishment of two mining bases. With larger maps like Frost and Deadwing FE-builds became very popular in PvZ.
The larger the choke, the more buildings needed to wall, meaning the wall will be slower. You could choose to sacrifice tech or economy, if you want to complete it more rapidly.
Pylons are not optimal as part of a wall-in in PvZ, as these make Baneling Busts more effective.
Make sure to place the buildings carefully. A simple slip up such as placing the first Pylon too far back can be fatal. Make certain the cannon covers all of the buildings from melee attacks. If the map allows it, leave a single space open for a Zealot so no buildings must be destroyed for units to get in and out of the base. If a wall-in building must be destroyed, the Cybernetics Core is usually the best option. The Core must be rebuilt somewhere else, of course, as it is an important tech building.