(uranography) Winter Triangle - a bright asterism of the northern winter sky. Its corners are the stars Betelgeuse, Procyon, and Sirius.

(uranography) Summer Triangle - a bright asterism of the northern summer sky. Its corners are the stars Altair, Deneb, and Vega.

Kyūjitai form of 大二十面半十二面体: great icosihemidodecahedron

Kyūjitai form of 体面: face

Kyūjitai form of 正四面体: regular tetrahedron

twenty years old

the twentieth day of the month / twenty days / Short for 二十日鼠 (hatsuka nezumi): a house mouse

consist of; be composed of / reach; be concluded / be buildable; be constructible

something that occupies three-dimensional space (is not two-dimensional) / (geometry) solid

Kyūjitai form of 正百二十胞体: 120-cell; regular hecatonicosachoron