Sea urchins
Calcareous techas of echinoderm made of a set of calcareous plates that form a kind of stiff, protective clover (the so-called dermal skeleton) with spines. From the point of view of symmetry, the sea-urchin has a prismatic three-dimensional symmetry; a photograph taken from the right point of view evokes a dihedral symmetry of type D5 (more evident on that on the left).
© matematita
The image belongs to the sections...:
Animals (Anthology of images)
Animals (Symmetry)
