duī jī
to pile up
to heap
accumulation
zuì mì duī jī
close-packing of spheres (math)
liù fāng zuì mì duī jī
hexagonal close-packed (HCP) (math)
miàn xīn lì fāng zuì mì duī jī
face-centered cubic (FCC) (math)
duī jī rú shān
to pile up like a mountain (idiom)
a mountain of (paperwork etc)
a large number of sth
duī jī mù
to play with stacking blocks