A diagonal loop is very similar to the vertical loop, except instead of drilling the holes vertically down, they are arrayed out diagonally to form more of a cone shape under the ground.

They still require the small pit to be dug a few feet underground, and a directional boring machine comes in to drill the holes diagonally.

This method is also very popular in DX systems because of the small footprint, which is minimally invasive to landscaping, requires little land, and is quick to install. It also makes geothermal accessible to more locations, opening the technology to more people.