The phrase "a peculiar shape" is correct and usable in written English.
You can use it to describe an object or form that is unusual or distinctive in appearance.
Example: "The artist created a sculpture with a peculiar shape that caught everyone's attention at the gallery."
Alternatives: "an unusual form" or "a strange outline."
And "'Miliband's knob is a peculiar shape', says a doctor".
Ever the good sport, Cumberbatch has owned up to it, conceding that his head is a peculiar shape.
Sometimes a piece of fruit with a peculiar shape will catch an artist's eye and suggest an entire sculpture.
In species with large upper canines, the most anterior lower premolar assumes a peculiar shape known as sectorial, functioning as a hone for the scythelike canine.
Into the impasto paint around his head Jo carved a peculiar shape - the halo of a saint, or perhaps more fittingly, a martyr.
Resistance presents a peculiar shape which appears to have an interference effect not observed before.
Why are so many congressional districts such a very peculiar shape?
A structure of peculiar shape called the Bent, Blunted, False, or Rhomboidal Pyramid, which stands at Dahshūr a short distance south of Ṣaqqārah, marks an advance in development toward the strictly pyramidal tomb.
The SEM images of fresh and spent CeP(2.5) did not show any peculiar shapes of cerium phosphate particles.
They concluded that although in some systems contact angle hysteresis was due to surface roughness and its mechanical or chemical heterogeneity, the hysteresis could be found even on homogeneous perfectly flat surfaces as a consequence of the peculiar shape of the Derjaguin isotherm in the partial wetting case".
Given their peculiar shape, an Arabian legend has it that "the devil plucked up the baobab, thrust its branches into the earth, and left its roots in the air".
