Islamic art creators will make deliberate imperfections in the design because of the belief that nothing is perfect but Allah. Muslim rug weavers will often omit a line of the design or place a color in the wrong place to represent the idea that we are imperfect humans and need God’s perfection in our lives. It is a way of honoring our connection to God. In architecture, one will often find an incorrect angle in the geometric patterns on Mosque walls and ceilings.
Sometimes, these flaws are very slight, and you have to look hard to find them, but they are there. Islam is not the only culture that believes in the intentional inclusion of an imperfection in the design. The Native American Navajo rug weavers also believe this. African American quilters used to put imperfections in their quilts because they had the belief that perfect quilts were unlucky.
This principle of including intentional rug imperfections is not prominent or practiced in every place where antique carpets were made. It all depends on whether Islam was the dominant religion and how strict the local leader regarded adherence to Islamic practice. Sometimes a flaw is just a simple human error. It shows that we are not machines and that the piece is the product of human hands.
When weaving carpets, if you discover a mistake, you are not likely to rip out six months of work to fix it. When you find rug imperfections in an antique carpet, you will have to decide for yourself whether it is intentional, or whether it is simple human error. Either way, rug imperfections make the carpets much more interesting and unique than something produced by a machine.