Normally, clothes would be a difficult choice for enchantment. Most Wizards would favour good solid metal for holding their enchantment, not just for the solidity of form but also because one piece of metal is one piece of metal but one item of clothing is technically numerous strands woven together and fixed in place by knot and stitch. But Ulgu, you theorize, is entirely at home with flexibility and ephemerality, so you set out to weave your oft-used spell of Aethyric Armour into your robes of office. You do have to make some preparations beforehand, so a few copper coins are exchanged for a set of needles and thread and you try your amateur best to sew sigils and runes into the lining, and you quickly develop a grudging admiration for those that practice the seamstress' art. It's a lot harder than it looks.
You're quickly proven wrong in your hypothesis, as a few days later you find that even with the sewn sigils to anchor the enchantment, the slightest wrinkle shatters the partially-formed enchantment and releases the magic to earth on the strips of iron that adorn your workbench for exactly that purpose. You frown as you examine the robes for any trace of magic left within them. Theoretically the enchantment fully-formed would be more stable, but that would require you to finish the long process of enchantment before the robes move even slightly. You consider various ways of trying to hold the robes immobile while still giving you access to the entire thing, before you shelf the idea and decide to try another approach.
An outlay of a few silver coins gets you a good leather skin, which you slice into a series of squares. Being originally part of an animal, it would theoretically retain magical energies better than most, and would retain the connection between the squares as they were once part of the same animal. Using reflected and concentrated sunlight, you slowly and carefully burn the appropriate sigils into each piece, doing your best to ignore the smell.
You need to put the pieces aside and work out on paper the correct way to divide the spell up so it can be split between different squares and still combine back together, which takes days of work as you convert the spell to thamaturgic equations and then try to find the best way to split it, and then convert the divided fragments back into pieces of incomplete spellcraft which then have to be made into enchantment, but you're unable to find a way to make an enchantment both self-contained and fragmented, so you have to go back to the beginning and convert the process of enchantment into thaumaturgic equations so you can derive that into fragments. By the time it's complete you're wondering whether the holding-the-robes-immobile thing would have been easier, but you press on.
Each of the squares of leather, when enchanted, is magically useless; it's only in combination with the 15 other leather squares and the 15 other fragments of the enchantment that they combine to form a working piece of magic. Or so the theory goes, and you've no way to check whether it works until all sixteen pieces are enchanted, and each square is a full day's work in itself. A week passes, then another, and finally you've got the end result ready for testing. You impatiently sew each of the squares into place in the lining of your robes and then wear them, feeling the unfamiliar weight they add to your usually so familiar robes. Then you press down on the square of leather on your left hip, and the familiar grey sinks into inky black as shadow rises from the weave of the fabric and spreads over your exposed skin. An experimental knife-cut on a sleeve fails to penetrate it, and then another on your palm similarly fails to cut, and you smile.