Signal wire connects from your button to your joystick controller PCB. A ground wire accompanies it to regulate electricity so you or another source doesn't become part of the conduction. Unlike signal wires which must be separated to reflect the exact button being pressed, ground wires can be daisy-chained together. This solution is now available as a 30 22 AWG connection wire.
Each connection point contains a .110 quick disconnect and nylon sleeve. With 30pcs, you have enough connections to wire three 8-button configurations, or four 6-button layouts. The wire can be cut in a number or ways to accomodate your project. The end wire is over 2 feet long, which can be cut if not needed or requires resizing.