Slot = document.createElement("slot");
firstSlot.name = "firstSlot";
const secondSlot = document.createElement("slot");
secondSlot.name = "secondSlot";
const belowSlots = document.createElement("div");
belowSlots.innerText = "belowSlots";
shadowRoot.appendChild(aboveSlots);
shadowRoot.appendChild(firstSlot);
shadowRoot.appendChild(secondSlot);
shadowRoot.appendChild(belowSlots);

const elementsInFlatTreeOrder = [host, aboveSlots, firstSlot,
  slottedToFirstSlot, secondSlot, slottedToSecondSlot, belowSlots, 