Nets

$\{x_i{\}}_{i\in I}\text{NET}\underset{\text{VFOs}}{\underbrace{I}}\to X$
$x\in \overline{X}⟺\exists \text{NET}\underset{\in X}{\underbrace{x_i}}\to x$
$I$ = neighbourhoods of $x$ with $A\ge B⟺A\subset B$.

$\{\varnothing ,X\}$ - all nets in $X$ will converge to all points in $X$.