This shape is called a muoctahedron, in other words, a hexagonal four-piece square hole twisted polyhedron.

His feelings are always warm, giving me a sense of security.

He shot the pellet with a slingshot.

Seeing his failure, she felt schadenfreude.

Alkenes, also known as olefin hydrocarbons, play an important role in organic chemistry.

Alkynes play a very important role in organic chemistry.

In chemistry class, I learned about alkanes.

Alkynes play an important role in organic chemistry.

Alkenes play an important role in organic chemistry.

Alkenes play an important role in organic chemistry.