The practice of blocking outwardness to reveal inner Light :
yasya kasyendriyasyāpi vyāghātāc ca nirodhataḥ |
praviṣṭasyādvaye śūnye tatraivātmā prakāśate || 89 ||
"By stopping any of the sense powers
by contradicting (their natural outward flow),
when one enters the non dual Void,
there and then the Self shines."