Have you ever seen crystallic cannons? Many haven't, because it is a bit useless in maps, but it looks cool. It is basically what the cannon looks like before it is fully warped. This tutorial will help you in that process of creating one or many crystallic cannons.
Basically, This is the easier version and would probably take more time. Place individual locations for where the cannons are going to be created. Why? Because it would probably stop bugs and allow creations of many cannons. Now for the triggers.
Make sure you have the pylons near the cannons, unless you want pylonless cannons, which can be done by individually enabling them with their own individual locations and trigger. If you do want to use the pylons, make sure they are rebuilt. Keep in mind, it takes about 850 to 1000 miliseconds from for 1 second for the cannon to be built. Try Different numbers for different designs and styles. You can also create other crystal buildings useing the same method, as long as they require a pylon. Crystal cannons cannot be manually controlled, only auto attack. Sort of like bunkers. Crystal buildings cannot upgrade, create units or have vespene gas/minerals returned to them.