Spectacular Waterfall Billboard Presents A Powerful Message. Nature by Numbers Movie. Slow Motion Lightning Is Super Awesome - imgbit.com. I See You… You may or may not have seen this by now, but some average Joe built a sentry gun out of some servos, a laptop, a paintball gun, and a whole lot of ingenuity (and I’m sure some optical sensor equipment). But what I love the most about it is: He chose to use the Portal Sentry as the boot up/ready sound, andHe/they then play (painful) games with it to try and test if they can defeat it through trickery. I couldn’t help but think that this is probably the safest real live test of what it must feel like to go up against the Portal Sentries.