Here, Kai is working on the Prithvi Yantra (पृथ्वी यन्त्र) subject. Although traditionally red, in our tradition it's painted yellow, symbolizing the earth element. The yantra includes the Devanagari letter लं (LAM). Bhuta Shuddhi (भूत शुद्धि) involves the cleansing of the gross elements in your body: earth (पृथ्वी), water (जल), fire (अग्नि), air (वायु), and ether (आकाश). In this case, as shown in the picture, it's about practicing Trataka (त्राटक) on the Prithvi Yantra. The physical manifestation of the Prithvi Yantra, its Rupa (रूप), means form and color. It is a yellow square. The sound of Prithvi is लं (LAM).
She is intently staring at the Prithvi Yantra. So, what's the point of this practice, this focused gazing at the Prithvi Yantra? The aim is to inhale, absorbing the color yellow and the Rupa, the form, the square, into your body. Simultaneously, you are in various ways absorbing the sound लं (LAM), the Bija mantra (बीज मंत्र). In this left-handed tradition, after completing all variations of this practice, it is also performed during sexual intercourse, where you work with these colors and sounds. However, this is a secret tradition, and I'm not really able to speak about it, as it could potentially be misused. But this pertains to the left-handed variation of Prithvi as part of Bhuta Shuddhi Dharana (भूत शुद्धि धारणा).