What is a tetradiplon and why is that important?
There is significant evidence that the cloth known as the Image of Edessa was folded as shown below. One piece of evidence, from the tenth century, is the painting of Abgar receiving the cloth with the very strange centering of a face on a landscape orientation as it would be if the cloth was folded as shown below.
Is a tenth century painting valid for an event that happened centuries before (if it happened this way at all). The answer is yes if we remember that the Image of Edessa was moved from Edessa to Constantinople where is was available to artists.
We must also take note of the fact that the Acts of the Holy Apostle Thaddeus, written in the early part of the 6th century, refers to the cloth as a tetradiplon, meaning it was folded into eight equal sections (doubled in fours, literally). See: Extract from the Acts of the Holy Apostle Thaddeus
John Jackson, a physicist from Colorado, found several folding creases on the Shroud when he examined the Shroud in 1978 with raking light. Some of the creases were particularly distinct and ran across the width of the cloth. If you follow the this-way and that-way of the creases Jackson found as shown below, you end up with a folded cloth that is eight layers thick. It is a stack of cloth approximately 3½ feet wide and 1¾ feet high.