An illustration of a hen, cat, dog and horse standing on top of one another to see into a window.

"A complex crystal of apatite with the faces of a third-order pyramid upon it." — Ford, 1912

"Hexagonal; tri-pyramidal. Crystals usually long prismatic in habit; sometimes short prismatic or tabular.…

"Tetragonal. Usually shows a combination of prism of second order, pyramid of first and basal plane."…

"Orthorhombic. Acicular pyramidal; consisting of a prism terminated by a combination of a very steep…

An image of a bald cypress, in pyramidal cultivated form. It is otherwise known as taxodium distichum,…

Illustration of a conical bifrustum created by three parallel planes of circles with the middle plane…

Illustration of a decagonal bifrustum created by three parallel planes of decagons with the middle plane…

Illustration of a hexagonal bifrustum created by three parallel planes of hexagons with the middle plane…

Illustration of a octagonal bifrustum created by three parallel planes of octagons with the middle plane…

Illustration of a square bifrustum created by three parallel planes of squares with the middle plane…

Brawl among Egyptian boatmen. Carving from the tomb of Ptah-hetep during the Pyramid age.

"Tetragonal. Common forms are prisms and pyramids of first and second orders." — Ford, 1912

"Hexagonal-rhombohedral. Crystals usually prismatic in habit or tapering hexagonal pyramids." —…

"The forms present upon it are two pyramids of different slope but each intersecting all three of the…

An illustration of a cube divided into 6 equal pyramids to illustrate how volume can be found.

"Cyrus caught sight of his brother Artaxerxes, whose person was revealed by the flight of his troops,…

"This form consists of twelve isoceles triangular faces, each of which intersects two of the horizontal…

A flashcard featuring an illustration of a Pyramid with a Hexagonal Base

A flashcard featuring an illustration of a Pyramid with a Pentagonal Base

A flashcard featuring an illustration of a Pyramid with a Rectangular Base

A flashcard featuring an illustration of a Pyramid with a Square Base

A flashcard featuring an illustration of a Pyramid with a Triangular Base

Diagram used to prove the theorem: "The volume of the frustum of a pyramid (cone) is equal to the sum…

The frustum of a pyramid is the portion of a pyramid included between the base and a section parallel…

The frustum of a triangular pyramid is equivalent to the sum of three pyramids whose common altitude…

Two pyramids and a sphinx near Gizeh, Egypt, built during the 25th century. These three structures rank…

Illustration of a right hexagonal pyramid that has been cut by a plane parallel to the base. The lower…

An image of a hexagonal pyramid stretched out. The length of the edges are equal plane, and intersects…

Genus Juniperus of the cypress family Cupressaceae. This juniper is in pyramidal form, found in Potomac…

"The third pyramid on the ridge of Gizeh was built by Menkera, a successor of Khafra and fourth or fifth…

"Prisims with edges parallel to neither of the axes OX and OY...are usually called hemi-pyramids." -The…

Illustration of a right octagonal pyramid, with hidden edges shown, that has been cut by a plane parallel…

Illustration of a right octagonal pyramid that has been cut by a plane parallel to the base. The lower…

Illustration of a hollow octagonal pyramid that has been cut by a plane parallel to the base. The top…

Diagram used to prove the theorem: "If a pyramid is cut by a plane parallel to the base, the edges are…

A volume of a truncated right triangular prism is equal to the product of its base by one third the…

A volume of a truncated right triangular prism is equal to the product of its base by one third the…

Diagram showing how "A truncated triangular prism is equivalent to the sum of three pyramids whose common…

A truncated triangular prism is equivalent to the sum of three pyramids, whose common base is the base…

A truncated triangular prism is equivalent to the sum of three pyramids, whose common base is the base…

"An orthorhombic pyramid has eight triangular faces, each of which intersects all three of the crystallographic…

An architectural structure of solid masonry, built for various purposes in different parts of the world.

"If a pyramid be cut by a plane, parallel to the base, so as to form two parts, the lower part is called…

"A pyramid is a solid whose base is a polygon, and whose sides are triangles uniting at a common point,…

Illustration used to compare the volumes of a pyramid and a prism by emptying sand from the pyramid…

"a shows a young tree with its second year's growth, the upright shoot of the maiden tree having been…

"The pyramids of Egypt are well entitled to a place among the most interesting curiosities in the world.…