Negative space helps create more space and draws more attention to one specific thing even though there can be multiple things within the piece
The answer is it represents the Lokeshvara, Lord of the World. Lokeshvara is a multi-armed form of Avalokiteshvara that seems to have been famous in Nepal since the middle ages. The name advocates that he is the lord of the world with reliable noose which leads grief sentient beings to insight.
It typically has three movements.