Verse 3.11

सर्वार्थता एकाग्रातयोः क्षयोदयौ चित्तस्य समाधिपरिणामः ॥११॥

sarvārthatā ekāgrātayoḥ kṣayodayau cittasya samādhi-pariṇāmaḥ ॥11॥

The weakening of scattered attention and the rise of one-pointed attention

in the citta is the transformation towards samadhi

Verse 3.12

ततः पुनः शातोदितौ तुल्यप्रत्ययौ चित्तस्यैकाग्रतापरिणामः ॥१२॥

tataḥ punaḥ śātoditau tulya-pratyayau cittasya-ikāgratā-pariṇāmaḥ ॥12॥

When rising and falling thought processes are in balance, one-pointed consciousness emerges. Maintenance of awareness with keen intensity from one-pointed attention to no-pointed attentiveness is ekagrata parinama.

Consciousnes swing between multi-faceted and one-pointed attention.

When one-pointed attention is established, multi-faceted attention disappears;

Observing these alternations and learning to hold steadfastly to singlepointed attention is the second phase of the transformation: samadhi parinama. 

Citta has two properties, dispersiveness (sarvarthata citta) and onepointedness (ekagrata citta) , with which it can direct its attention externally or internally. It can fuse these two powers into one, to move towards spiritual absorption.

Citta takes the form of any object seen, observed or thought of. It can spread itself as much as it desires. When it spreads, it is multi-faceted; when it remains steadily focused, it is one-pointed. When it is scattered, distraction and restlessness set in. This restlessness can be subdued, but nothing which exists can be destroyed; it can only be transformed: made to disappear or fade by thoughtful attention, enabling the stream of conscious restfulness to flow steadily. 

In this way, consciousness is influenced by its own action.

It forms the habit of absorption in a single thought, which prepares one for spiritual absorption. This type of attention, samadhi parinama, stabilizes the state of restfulness.

In nirodha parinama, the emergence of thought-waves is restrained and stilled. In samadhi parinama, the intervals between the emergence and the restraint of thoughts and vice versa are studied. From this study emerges a stillness which leads to silence. One should know that stillness is rigidity

and silence is passive and meditative. 

In the state of silence, the fragrance of the soul emerges as the centre of attention. This is ekagrata parinama

Even in this focus on the property of citta alone, the sensitivity of attention may be intense or light. To maintain a steady, uninterrupted flow and intensity of attention in citta is the third phase of transformation.

At times, consciousness is thoughtfully silent but then it suddenly gushes out into vibrant activity. In a split second, this activity may be controlled and balance regained. This control requires effort, and effort involves time.

By skilful practice, the depth of silence which at first appears only in glimpses, is made to permeate and fill the entire citta. Then the feeling of time disappears. Past and future are reabsorbed into the timeless.

Mind and time are interdependent. As the moments of the mind come to an end, so does time. Citta and the seer (atman) are the two sharp edges of a blade. In one-pointed attention (ekagrata samskara) the energies of the seeker and the seer become one.

PATANJALI YOGA SUTRAS