tetrahedron

"The math teacher explained that an equilateral triangle has three sides that are the same length. "

"The school's fundraising project aims to renovate the library in several stages. "

"This beer has no equal."

"The professor's lecture focused on platonic ideas about the ideal society. "

"My son is learning about geometry in his math class, studying how shapes relate to each other in space. "

"He is a student of life."

"By now, you must surely know which is which."

"The teacher showed us a colorful polyhedron with triangles and squares for faces. "

"The desk and chair in the classroom are made of solids. "

"The sergeant major is a regular in the British Army. "

"That girl has a pretty face."

"The art teacher asked the students to draw different shapes, including triangles. "