Furniture Attachments in Form of Tyt-Amulet and Djed-Pillars
Acacia
New Kingdom, Dyn. 18, ca. 1539 - 1292 B.C.
Provenance not known
Charlies Edwin Wilbour Fund, Brooklyn #37.253E a-c
Photo © Joan Lansberry, May 2008

From _Art for Eternity_, page 157
djed-pillar "An Egyptian hieroglyph, probably a manifestation of part of the spinal cord, that was a written form of the word for 'stability'. It was a commonly employed symbol in religious iconography."

  
From _Reading Egyptian Art_, Wilkinson, tyet drawn by me...

From _Reading Egyptian Art_, Wilkinson, page 165
"In relief scenes, and in decorated objects, the djed was one of the most frequently used hieroglyphic signs, with alone or in conjunction with the ankh and was signs, or with the tiet - the so-called 'Isis knot'. The djed also had particular associations with Egyptian concepts of royalty. In the temple of Seti I at Abydos, personified djed signs are shown in the kind of heavy pleated clothing worn by royal figures (ill. 3), possibly as representative of the king himself."

(ill. 3):

(There is also a personified Was at Seti I's temple)

Here's a small amulet at the Brooklyn Museum featuring the Tyet:


Jasper Amulet in the Form of Tyt (back inscribed with hieroglyphs)
New Kingdom, XVIII Dynasty-XIX Dynasty
Dimensions: 2 3/8 x 1 x 1/4 in. (6.1 x 2.5 x 0.6 cm)
37.1272E, Charles Edwin Wilbour Fund
The front is viewable at the Brooklyn Museum website.
(Or here!)

Bob Brier tells about the preparations of the pharoah's mummy, in which this amulet was featured:

"About the king's neck were six collars and twenty amulets wound into the six layers of linen. After a "Collar of Horus" done in sheet gold, there was a necklace of four amulets strung on gold wire. First was a red jasper "knot of Isis." According to the Book of the Dead, whoever wears such a knot will have the protection of Isis and her son Horus and will be welcomed into the next world. The red represents the blood, magic, and power of Isis. Then there was a gold djed-column with magical inscription..." (_Ancient Egyptian Magic_, pages 193-194)

(The Brooklyn Museum also has some faience Djed pillar amulets.)
At that page I show faience djed and tyet amulets at the Metropolitan Museum.