In mathematics, a toroid is a surface of revolution with a hole in the middle, like a doughnut, forming a solid body. The axis of revolution passes through the hole and so does not intersect the surface. For example, when a rectangle is rotated around an axis parallel to one of its edges, then a hollow rectangle-section ring is produced. If the revolved figure is a circle, then the object is called a torus.
A toroid using a square.
A torus is a type of toroid.
In mathematics, a toroid is a surface of revolution with a hole in the middle, like a doughnut, forming a solid body. The axis of revolution passes through the hole and so does not intersect the surface.[1] For example, when a rectangle is rotated around an axis parallel to one of its edges, then a hollow rectangle-section ring is produced. If the revolved figure is a circle, then the object is called a torus.
The term toroid is also used to describe a toroidal polyhedron. In this context a toroid need not be circular and may have any number of holes. A g-holed toroid can be seen as approximating the surface of a torus having a topological genus, g, of 1 or greater. The Euler characteristic χ of a g holed toroid is 2(1-g).
This t-shirt is everything you've dreamed of and more. It feels soft and lightweight, with the right amount of stretch. It's comfortable and flattering for both men and women.
• 100% combed and ring-spun cotton (heather colors contain polyester)
• Fabric weight: 4.2 oz (142 g/m2)
• Shoulder-to-shoulder taping
• Side-seamed
Size guide
| |
XS |
S |
M |
L |
XL |
2XL |
3XL |
4XL |
| Length (inches) |
27 |
28 |
29 |
30 |
31 |
32 |
33 |
34 |
| Width (inches) |
16 ½ |
18 |
20 |
22 |
24 |
26 |
28 |
30 |
