1. Square
   Cylinder
2. Trapezoid
   Rhombus

It's interesting how the shape of a square has also been translated into different concepts totally unrelated to geometry. The most notable example is how "square" became slang for people who are generally seen as "not cool" or "not hip," which evolved during the early Jazz Age in the U.S.

1. Torus
   Octahedron
2. Pyramid
   Circle

The circle has long been known as a symbol of equality. Perhaps the most famous iteration of this idea is the "Knights of the Round Table" concept in the legendary story of King Arthur.

1. Dodecahedron
   Sphere
2. Rectangle
   Kite

A rectangle is very familiar to people who design buildings, as many structures look like this basic flat shape. There are buildings that look like a rectangle standing on its end, while some buildings mimic the shape of a rectangular shoebox in design. And, of course, many doors are rectangular.

1. Pentagon
   Oval
2. Heptagon
   Nonagon

The "Oval Office" is perhaps the most popular usage for the shape of the oval. For those who are not familiar, this is where U.S. presidents go to do their work in an office setup.

1. Pentagon
   Cone
2. Cuboid
   Cube

Perhaps the pentagon is the most famous polygon of all, thanks to the U.S. Department of Defense taking its shape for its office building. The Pentagon was built that way to conform to certain restrictions of the time, namely the topography of the area where it was originally supposed to be built.

1. Cone
   Triangle
2. Cylinder
   Star

A triangle is a basic shape, but it could also pertain to a particular musical instrument that takes this exact shape or form. This versatile shape has many applications in different fields, such as the method of triangulation used to determine the exact location of a point by assessing distances using a series of triangles.

1. Bolt
   Crescent
2. Octagon
   Ring

An octagon has eight sides, all with equal measurements. In UFC fights, this octagon is seen as a more flexible and fair shape than the traditional square ring of boxing.

1. Semicircle
   Sphere
2. Parallelogram
   Star

This flat shape is called a star, and it usually has five points. But there are different kinds of star patterns as well, with more points.

1. Trapezium
   Cross
2. Equal sign
   Trapezoid

Two bars that intersect each other at right angles, with the vertical bar usually longer, form a cross. In mathematical equations, though, when the two bars are of equal length, the symbol is a plus sign.

1. Diamond
   Kite
2. Heart
   Irregular quadrilateral

This is the symbol of the human heart in a figurative sense, even though it's rather far from the organic heart's real shape. But this approximation has been embraced by all cultures of the world, and it has come to symbolize love as well.

1. Arrow
   Decagon
2. Quatrefoil
   Trefoil

A combined triangle and rectangle can form the shape of an arrow. This universal shape is recognizable in many places in modern life, such as maps and road signs.

1. Cuboid
   Lens
2. Ellipse
   Crescent

The shape of the waxing moon is universally recognizable as the crescent. It's a commonly used symbol in religious iconography as well as in logo-making.

1. Annulus
   Arch
2. Hexagon
   Pentameter

Don't put a hex on someone if they don't know that the hexagon is a polygon with six sides. We're mostly familiar with this shape because it looks like the shape of honeycomb design, but sometimes it's used to indicate cellular phone technology.

1. Swastika
   Cube
2. Sphere
   Rectangular prism

The swastika is an ancient religious shape that takes the form of a cross, but with the edges bent, facing clockwise or counterclockwise. It was recognizable in Asian religions for thousands of years, until the Nazi Party adopted it in the early part of the 1900s for its now-controversial logo.

1. Line
   Cone
2. Hexahedron
   Trapezoid

A trapezoid is a special type of quadrilateral. While a quadrilateral is any four-sided figure, a trapezoid is a four-sided figure in which exactly two of the opposite sides are parallel.

1. Dodecahedron
   Rhombus
2. Frustum
   Equilateral triangle

A rhombus is a shape with four equal sides, but it's not necessarily a square. While a square's inside angles are all right angles, a rhombus doesn't have to contain right angles. A rhombus can be diamond-shaped.

1. Pentagram
   Nonagon
2. Parallelogram
   Enneagram

A parallelogram is a quadrilateral which, by its very name, signifies that the opposite sides should be parallel to each other. However, the corners don't have to be right angles.

1. Ring
   Hexagon
2. Bolt
   Arrow

When two circles are drawn, with a smaller one inside a bigger one, that usually symbolizes the ring shape. The ring could be simply drawn flatly like that, or it could also be rendered as a 3D image to show the surface.

1. Polyhedra
   Raindrop
2. Cone
   Prism

A cone is a three-dimensional kind of shape in geometry. It has a circle for a base, and then the "sides" all extend and meet up to reach the point or tip, called the vertex or apex.

1. Cube
   Cylinder
2. Cone
   Double star

A cube is basically a square, only in its 3D version. Thus, instead of merely having the flat sides being all equal in measurement, all faces and sides of the 3D shape should be equal here.

1. Octahedron
   Icosahedron
2. Rhombic dodecahedron
   Right triangle

A right triangle has one right angle, meaning its measurement is 90 degrees. The two other angles are smaller than 90 degrees, sometimes both 45 degrees in measurement, sometimes not. In any case, the other two angles combined must equal 90 degrees.

1. Tetrahedron
   Cylinder
2. Hexagonal pyramid
   Parallelepiped

The geometric shape known as a cylinder is usually elongated, with two of its parallel bases being circles. The curved elongated surface gives this shape the 3D look, since it appears solid, not flat.

1. Cone
   Pentagonal prism
2. Pyramid
   Semicircle

A pyramid is classified as a polyhedron, which means that it is a solid kind of shape that has several plane faces. A pyramid has a polygon for a base, plus four triangular planes.

1. Semicircle
   Hexagonal prism
2. Sphere
   Hexahedron

Think of this bubble as a flat shape. In two dimensions, half of a circle is a semicircle.

1. Arch
   Cuboid
2. Kite
   Ring

You'll know you have the perfect kite when you can draw a full circle inside of it, touching all four sides. A kite shape has two pairs of equal sides that are adjacent to each other.

1. Annulus
   Moon
2. Lens
   Heptagon

A heptagon is another kind of polygon, which means it's flat. This one must have seven sides, which could be in the form of a regular or irregular heptagon.

1. Isosceles triangle
   Right triangle
2. Scalene triangle
   Equilateral triangle

An isosceles triangle is easily identifiable, much like an equilateral one. While an equilateral triangle's three sides are all equal in length, the isosceles triangle has only two equal sides.

1. Less than
   Greater than
2. Equal sign
   Divided by

Two short horizontal bars or lines of equal length, drawn parallel to each other and close together, form the universal symbol called the equal sign. In mathematical calculations, the values on each side of the equal sign must be the same. Sociologically speaking, it has also been used as a symbol by communities advocating for equality in treatment, such as the women's movement and the LGBTQ+ community.

1. Cuboctahedron
   Rhombicuboctahedron
2. Square antiprism
   Sphere

A sphere is basically a circle that's in a solid 3D format. This geometric shape is used in sports that require a round ball, such as basketball and baseball.

1. Triangular pyramid
   Scalene triangle
2. Square pyramid
   Triangular prism

A scalene triangle has three sides, but all of them differ in length. Equilateral and isosceles triangles are never scalene.

1. Trefoil
   Concave
2. Complex
   Parallelogram

Girl Scouts know the shape of the trefoil all too well, since it's incorporated in their logo. A trefoil is basically three circles or similar shapes of the same size, joined together in overlapping fashion to form one figure.

1. Pentagram
   Enneagram
2. Rhomb
   Decagon

If a decade has ten years, a decagon must have ten sides, so it's the prefix here that helps you to remember this kind of polygon. A decagon can be flat, but there is also a three-dimensional kind called a decagonal prism.

1. Diamond
   Hemisphere
2. Quadrangle
   Tetragon

A hemisphere is easier to remember if you consider the shape of the Earth, which is basically a sphere. Imagine the equator cutting the global sphere in half, and you'll get two hemispheres - the northern and southern. Since the prime meridian cuts across the globe vertically, it divides the Earth into the eastern and western hemispheres.

1. Quatrefoil
   Cyclic
2. Equilateral
   Convex

A quatrefoil shape has four equal-shaped circles or simple shapes that partly overlap, forming a kind of cross-like image, but rounded. This shape is commonly used in art, architecture, heraldic designs and religious symbols.

1. Equiangular
   Concave
2. Triangular prism
   Disc

A triangular prism resembles the shape of a tent in real life - especially the simple long one you pitch when you camp out. It has triangles of equal measurement on both ends, then the sides and bottom are composed of three rectangular faces.

1. Obtuse
   Rhomboid
2. Trapezoid
   Icosagon

An obtuse triangle contains one obtuse angle, meaning an angle that is greater than 90 degrees. A triangle can't possibly contain more than one obtuse angle, though, since the three angles of a triangle must always add up to 180 degrees.

1. Triskaidecagon
   Octagram
2. Cuboid
   Dodecagram

A cuboid is generally the 3D version of a flat rectangle. The sides don't have to be squares or even equal rectangles, but there must be six flat sides in total. If all six sides are squares, then you have a cube!

1. Raindrop
   Pentagram
2. Decagram
   Hail

The commonly recognized raindrop shape consists of a very heavy rounded bottom that tapers to a point at the top. It can also symbolize water, not just rain.

1. Trapezium
   Frustrum
2. Bolt
   Golygon

A common shape seen around the world is the lightning bolt, usually drawn with several diagonal lines facing the same direction, connected to each other by smaller lines. It can be drawn in an outline or in solid form, just like Harry Potter's famous forehead scar.