1. Oval
   Rhombus
2. Crescent
   Circle

A perfect circle is one in which everything is equidistant from one middle point. Some people will get technical and say you can never draw a perfect circle because the line weight of the ink or whatever you drew it with will be inconsistent and imperfect, but that's nitpicking.

1. Hexagon
   Octagon
2. Parallelogram
   Pentagon

A stop sign and a UFC fighting ring both have the same shape of an octagon. It's an 8-sided polygon, hence the "octa" part of the name. The sum of all internal angles in any octagon is 1080 degrees while the external angles add up to 360.

1. Obtuse
   Right
2. Equilateral
   Acute

Al three angles must be less than 90 degrees for a triangle to be considered an acute triangle. It's a kind of oblique triangle and cannot be a right triangle because none of the angles are exactly 90 degrees.

1. Sphere
   Pyramid
2. Rectangle
   Crescent

A pyramid is probably the most famous polyhedron shape thanks to the pyramids in Egypt. It has a polygon base and flat sides that meet at the apex or point on the top of the pyramid. The shape allows for very efficient weight distribution when it comes to building.

1. Parallelogram
   Rhomboid
2. Square
   Trapezoid

A perfect square has four sides of the same length and four even 90-degree angles. If the angles weren't even it could be slanted and become a parallelogram and if the sides aren't even but the angles are, then it's a rectangle.

1. Scalene
   Isosceles
2. Kepler
   Obtuse

Acute refers to angles below 90 degrees while obtuse refers to those above. An obtuse triangle will still have two acute angles because mathematically that's the only possible way to join the shape with an obtuse angle.

1. Oval
   Sphere
2. Hexagon
   Dodecahedron

Bees are crafty little creatures and they form their honeycombs in natural, six-sided hexagons. The shape also appears in nature in things like naturally forming basalt columns and in crystals like cinnabar and beryl.

1. Cone
   Cylinder
2. Torus
   Sphere

Cones taper smoothly from a flat base to a single apex point. The structure is one that allows for strength and stability focused on the point. One of the most prominent cones you'll see in nature is in a storm like a tornado.

1. Crescent
   Icosagon
2. Cylinder
   Rhombus

A rhombus is a shape that has four sides all of the same length. In very simple terms what we commonly understand as a diamond shape, as in the suit from a deck of playing cards, is a rhombus.

1. Equilateral
   Scalene
2. Kepler
   Polygonal

All the measurements of a scalene triangle have to be different. No two sides share the same length, no two angles share the same number, either. A scalene could be a right triangle, but it doesn't have to be.

1. Paralleogram
   Dodecagon
2. Polyhedron
   Tetrahedron

When polygons meet the third dimension they become polyhedrons. A polyhedron has straight edges and sharp corners and comes from two Greek words "poly" meaning many and "hedron" meaning face.

1. Oval
   Sphere
2. Cylinder
   Prism

You can play a little fast and loose with the rules of an oval as it's just any shape that tends to be egg-like. There are some more mathematical definitions of an oval when you start talking about things like a Cartesian oval or a Cassini oval.

1. Triskaidecagon
   Heptagon
2. Pentagon
   Tetradecagon

If triskaidecagon reminds you of the word triskaidecaphobia, it's because both of them are based on the number 13. Phobia is fear of the number 13 while a triskaidecagon is a polygon with 13 sides.

1. Prism
   Rhombus
2. Rectangle
   Torus

A rectangle is one of the simplest shapes in geometry and one of the most useful. Boxes, bricks and planks of wood are generally all made in a rectangular shape so they've definitely proven their worth at least in terms of construction.

1. Right
   Kepler
2. Parallel
   Obtuse

By definition a right angle is a 90-degree angle, so a right triangle is a triangle with one 90-degree angle. If the length of the sides are integers, then it also qualifies as a Pythagorean triangle as well.

1. Rhomboid
   Icosagon
2. Trapezoid
   Torus

In technical terms you make a torus by "revolving a circle in three-dimensional space about an axis that is coplanar with the circle." In very simple terms it's a donut, or a three-dimensional ring. The plural is also tori, which is fun for anyone named Tori.

1. Sphere
   Tetrahedron
2. Polygon
   Kite

A kite is a quadrilateral shape with two distinct pairs of sides that are of equal length and adjacent to each other. Put in other terms, you have a long triangle with the base against the base of a shorter triangle to make a kind of a skewed diamond. You can also call it a deltoid if you want.

1. Tetrahedron
   Megacube
2. Hypercube
   Dodecahedron

A hypercube is what you call a four-dimensional shape analogous to a three-dimensional cube and a two-dimensional square. It's also known as a tesseract which you might remember from the "Avengers" movies. A cube has six square surfaces while a hypercube has eight cubed cells.

1. Pentagon
   Hexagon
2. Octagon
   Polyform

The Pentagon is named for its five-sided shape, a pentagon. Though the shape does have an artificial quality to it, you can find it frequently in nature. For instance, if you cut a cross-section of okra it will be in a pentagon shape, and flowers like morning glories bloom in a pentagonal shape as well.

1. Scalene
   Pythagorean
2. Kepler
   Eqyilateral

The squares of the sides of a Kepler triangle are in geometric progression according to the Golden Ratio. What's the Golden Ratio? Tha's what happens when the ratio of two quantities is the same as the ratio of their sum to the larger of the two quantities.

1. Equialteral
   Hexagram
2. Parallelogram
   Trapezoid

It makes sense that a parallelogram is defined by parallel sides. The opposing sides are of equal length and it's officially a rhomboid. It can't have a right angle or it'd be either a square or a rectangle.

1. Lozenge
   Dodecahedron
2. Icosagon
   Cyclic quadrilateral

If a shape has 12 faces on it, it's a dodecahedron. They come in a few varieties but a regular dodecahedron has 12 faces, 20 vertices, 30 edges, and 160 diagonals. It's a pretty common shape for dice in games like "Dungeons and Dragons."

1. Megagon
   Rhombus
2. Cylnder
   Prism

In a non-geometrical way, a prism is just a transparent piece of glass or plastic that can refract light. In geometry it's any polyhedron shape connected with an identical shape by parallelograms on the corresponding sides. The base can be any shape like a pentagon or a hexagon.

1. Tetrahedron
   Nonagon
2. Hendecagon
   Megagon

A hendecagon is an 11-sided polygon that can sometimes go by the name undecagon or endecagon, though those aren't the best choices since they merge Greek and Latin. The internal angles of a hendecagon add up to 147 and 3/11 degrees in total.

1. Scalene
   Acute
2. Obtuse
   Isosceles

At least two sides of an isosceles triangle have to be the same length but not all three sides. That said, all three sides could be and that would make it an equilateral triangle and technically a different shape altogether.

1. Hexagram
   Oxagram
2. Pentagram
   Tetradecagon

Pentagrams are sometimes called pentangles or pentalphas. They've been a popular shape throughout history used in ancient Sumerian cuneiform, Ancient Greece, Wicca symbolism and also associated with Satanism.

1. Megagon
   Decagon
2. Ultragon
   Superhedron

A megagon is the sort of shape you can't really draw and only exists in theory or computer models. With one million sides, if you were to draw one the size of the Earth itself it would still look like a perfect circle.

1. Lozenge
   Kite
2. Sphere
   Ovoid

A lozenge can be a straight synonym for a rhombus, which is what is often referred to as a diamond. But usually, to distinguish it from a rhombus, it refers to a thin kind of rhombus with two acute and two obtuse angles.

1. Tetrahedron
   Hexagon
2. Axis
   Quadrilateral

Quadrilateral is a very basic term for a four-sided shape which can include squares, rectangles, parallelograms, kites or other irregular shapes. As long as they have four sides they qualify for the label.

1. Trapezoid
   Decagon
2. Icosagon
   Crescent

A decagon is a ten-sided polygon which, in a pinch, you can call a 10-gon. It's not a shape that gets used for many things, though you can find dinner plates or mirrors that are made in decagonal shapes now and then.

1. Tetrahedron
   Cylinder
2. Cube
   Parallelogram

A cube is a very simple shape, the three-dimensional representation of a square with six even and identical faces. As far as three-dimensional shapes go, it's one of the most commonly used for blocks, boxes and tons of other things. Even salt naturally forms in cubes.

1. Nonagon
   Raspagon
2. Icosagon
   Heptadecagon

The 20-sided icosagon has internal angles that add up to 162 degrees. You may not have realized it but the Big Wheel on "The Price is Right" is an icosagon, meaning that geometry can really be worth something one day!

1. Tetrahedron
   Rhomboid
2. Torus
   Hexagon

A pyramid with a triangular base is also known as a tetrahedron. It has four triangular faces and six straight edges. It's the simplest kind of convex polyhedron and the only one that has fewer than five faces.

1. Oval
   Sphere
2. Circle
   Cylinder

A sphere is a three-dimensional representation of a circle. For a sphere to be perfect mathematically, every point on the surface has to be equidistant from the center. Planets and atoms are examples of spheres in nature.

1. Cylinder
   Crescent
2. Ovoid
   Pentagram

The crescent shows up a lot throughout history. Because of the way lunar cycles work, the crescent moon is the most prominent example but it's also used as a symbol for Islam and, very often, the shape croissants are baked in.

1. Pentangle
   Prism
2. Lozenge
   Trapezoid

A trapezoid is what you call this shape in North America but the rest of the world knows it as a trapezium. The sides can't be of equal length or otherwise you'd have a square plus two sets of parallel sides.

1. Oblique
   Pythagorean
2. Equilateral
   Isosceles

All three sides of an equilateral triangle are of the same length. That in turn means that all the angles are equal at 60 degrees each. You can call this a regular triangle as well, and like many shapes it's a polygon.

1. Convex regular dodecahedron
   Triakis icosahedron
2. Great stellated dodecahedron
   Kleetope

Most people will never run across a great stellated dodecahedron. Much the same as a square is analogous to a cube and a circle is analogous to a sphere, a pentagram is analogous to the great stellated dodecahedron.

1. Cylinder
   Sphere
2. Cube
   Cone

A cylinder is a pretty handy shape for holding things like Pepsi or beans, which is why so many cans are made as cylinders. It is essentially a circular prism. Cans are made in that shape because a cylinder is one of the most structurally sound shapes that exist.

1. Infinigon
   N-gon
2. Apeirogon
   Gonagon

This is one of those weird theoretical shapes that you're certainly never doodling on a napkin. It's still different from a circle which would have an infinite number of points that aren't necessarily sides, like what an apeirogon would have.