Bolted onto the back of the Horizon is a high-tension, spring-mounted kickstand that allows you to quickly and easily move the system flat on its backside by putting pressure on the top-front of the PC. (This action also automatically launches Aura, Lenovo's custom touch interface, described below.)
That's convenient, but the tension in the spring on this kickstand only makes it possible to place the device in three positions: flat on a tablet, perfectly upright, and slightly tilted back. To be fair, these positions are what most users will use, but if you want finer control of the Horizon's viewing angle, you won't be able to accomplish that.
The system uses its own weight (almost 19 pounds) to keep the kickstand from springing back when it lays in table-top mode, and it has enough tension and force that you'll find yourself surprised at how hard the stand kicks out when you stand it back up. It's not dangerous, but it feels that way from time to time.