Gather sand to form a tower, and gather stones to form a mountain.
The definition of gathering sand to form a pagoda: gathering fine sand to form a pagoda. Originally refers to children's tower building game. The latter is a metaphor for adding up a little and making a lot. Also known as "accumulation of sand to form a tower".
Source: "The Lotus Sutra: Convenient Products": "Even when children are playing, the sand is gathered into a Buddhist stupa."
Translation: Even when children are playing, the sand is gathered into a Buddhist stupa.
Extended information
Synonyms of gathering sand into a tower:
Gathering armpits into fur: [jí yè chéng qiú]?
It means fox armpit Although the skin underneath is very small, it can be gathered together to make a leather robe. Metaphorically, a little makes a lot.
From "Shenzi Zhizhong": The fox-white fur is not covered with the skin of a fox.
Translation: White fox fur coat, this is not the skin of a fox.