The solution is later in the article. > The insight that leads to a solution comes from the Jacobian. It's not a unform half disk. It has more weight away fro

The solution is later in the article. > The insight that leads to a solution comes from the Jacobian. It's not a unform half disk. It has more weight away from the Y axis. You can imagine it's painted with watercolors and you want to collect the same ammount of ink. In an uniform disk you have xx xxxx xxxx xxxxxx xxxxxx xxxxxx But in the weighted disk of the article the top and bottom are darker and the center lighter .. x..x x..x x..x Xx..xX Xx..xX Xx..xX but there are no strips like in my ASCII art, the shade changes slowly.