Don't know if he just mashed into that shape or bought a different shape pad.
I will say, I built a bucket polisher. I recommend a thick shag carpet for the bottom of bucket, cover it in microfiber, cover the sides of bucket with microfiber.
On the sides, I determined the direction of the spinning pad of the buffer. Started the microfiber in the same direction and then folded the microfiber under itself at the end each time to create a lip to agitate the balls some.
I put in 7 balls, hit w a few sprays of cleaner, put the polisher down on the balls and run for two minutes, repeat. This way I can rock the polisher around or tip the bucket. I can also still use the polisher for my vehicle.
Works great. If I needed more, I'd build a better one.