Spanda-vritti , and Spanda-karika may be attributed to the thinker Bhatta Kallata in the 9th century A. D. It is said that together with Somananda he was a student of Vasugupta, who is known as one possible author of the Shiva Sutras.
In the following select verses are contemplated based on available translations.
Spanda-karika (Stanzas on Pulsation or Stanzas on Vibration)
|| 3 ||
Your essence-nature, the Source of all you experience, flows equally
in all three states of consciousness: waking, dreaming, and deep
sleep, none of which are other than It. [In all these states,] the
Perceiver never departs from Its own essential nature. || 3 || 
Refer to A Treatise On Kundalini, paragraph “Kula Kundalini Vidya”, specifically to the reflection on movement and pulsation.