The robotic mower that powers the spider is confined to an area by the same concept as an invisible dog fence barrier, you stake down a singe wire in the area you would like the mower to stay within. On short notice I used the dog barrier wire found in the local hardware store because it is the same gauge and is colored green to blend in, but the mower companies sell extra wire also. A battery operated signal controller box will send a signal down the wire that sets up an invisible barrier. Run the single wire from a central point to outline the area you wish the spider to roam within and stake the wire down every couple of feet or more using plastic tent stakes or metal lawn staples. Stake the wire down in the area and pattern you wish to have the spider contained to and bring the end of the wire back to the starting point, forming a loop, where the ends will be stripped and screwed into a connector that plugs into the signal controller box. Stake the ends close together where they run to the controller, this cancels the signal out and the mower ignores this section of wire instead of following it to the controller. Hide the signal controller under some leaves, or in my case I placed it in a wooden decorative wishing well. Press the power button on the signal controller and you are ready to move the spider onto the lawn within the signal area. If you already have a wire area setup for mowing this section of lawn you can use this but I like to contain the spider to a smaller area that is closer to the view of my victims so I lay out a smaller area, disconnect controller from the normal lawn cutting loop of wire and connect it to the line staked down for the spider.