yoga sutras

The way I understand the breakdown of Yoga Sutra 1.2.
Yoga is the observation and control of thoughts streaming through the mind.
I use the words observation and control instead of restraint because I believe you have to be aware of your thoughts before you can control them. The word restraint is too one sided, meaning not to allow, but the word control denotes the choice of weather to allow or not to allow the thoughts to flow.

Yogas Citta Vrtti Nirodhah (1.2)
YOGAS (taken in context to mean the yogic experience - not the normal translation of Union)
Yoga is the experience gained by control over streaming thoughts.

CITTA (chitta - the mind)
ahamkara: the ego, buddhi: intellect or discriminative faculty, manas: desire - atttraction to outside things via the senses

VRTTI (vritti - thoughts)(1.6)
Five types of vrittis: pramana: right knowledge (1.7), viparyaya: misconception or wrong knowlege (1.8), vikalpa: verbal delusions (1.9), nidra: sleep (1.10), smritayah: memory (1.11)
Sources of Right Knowledge (1.7); pratyaksha: direct perception, anumana: inference, agama: tradition
Misconception (1.8) when knowledge of something is not based on its true form.(visual)
Verbal Delusion (1.9) an image that arises on hearing words without any reality as its basis. (auditory)
Sleep (1.10) a state of mind supported by cognition of nothingness.(one thought of emptiness in the mind)
Memory (1.11) when thoughts of something previously experienced comes back to consciousness (dreams or daydreams)

NIRODHAH (nirodhah - control)(1.12) Observation is gained through non-attachment and control of the thoughts is gained through practice.