You’ll see some online videos and writeups about poking a lot of holes in a plastic container, burying it (with the neck poking out above the ground), and filling it with water. This is a slow-release watering system but it does not work like an Olla. These DIY contraptions can distribute water underground and, if properly placed, the water from them can reach the root zone of nearby plants. But the water drains out much faster than an Olla, can go below the root zone quickly, does not operate on the principle of soil moisture tension (which can result in overwatering), the small holes (usually made with an ice pick) tend to clog up with dirt, and they need to be frequently filled.