CSS z-index paradox flower

Question

I would like to create a paradoxical effect via the z-index CSS property.

In my code I have five circles, like in the image below, and they are all absolute

Answer 1

Here's my go at it.

I also use a pseudo element positioned on top of the first circle, but rather than using clip, I keep its background transparent and just give it an inset box-shadow that matches the background color of the circles (silver) as well as a red border to cover the bottom right sides of the circle's border.

Demo

CSS (that is different from starting point)

.i1 { 
  position: absolute; top: 30px; left: 0px;
  &:before {
    content: '';
    position: absolute;
    z-index: 100;
    top: 0;
    left: 0;
    width: 50px;
    height: 50px;
    border-radius:  50%;
    box-shadow: inset 5px -5px 0 6px silver;
    border-bottom: solid 1px red;
  }
}

Final product