Quadraphonic Surround Speakers

I watched a video on quadraphonic sound. It's like the surround sound of the 1970s. Most surround sound systems these days are 5.1 or better.
I have collected a few too many speakers, so I decided to put another set to use. I already had two 4 ohm speakers on the sides of my computer monitor, and I decided to add two more on the other side of the room.
I purchased a 2x20W amplifier and installed it on the front speakers. The rear speakers are now using the old amplifier that used to be on the front speakers. The front speakers are used more so they needed a more efficient amplifier. the 2x20W class D doesn't need a heat sink. the 2x15 class A/B needs a heat sink and fan.
I used a 22 gauge 4 conductor wire running under the rug to the splitter box. I used an 18 gauge 2 conductor wire from the splitter box to the rear speakers. For the splitter "box" I used a section of wood from a peach tree with a 2 1/8 inch hole drilled in it.

I tested this setup with Minecraft. It was interesting to have the sounds of different Minecraft animals coming from different directions.  Hearing the ender dragon behind me was the most impressive.