MS Add. 1577 is a polychrome charm (yantra) against lightning made of seven intertwined letters (kūṭākṣara, monogram script): ya, ra, va, la, ma, kṣa and ha.
The verso bears the following four-line stanza in the sragdharā metre (with caesurae marked by a small dot), listing each letter and explaining its symbolism:
yaṃ kāraṃ mārutākhyaṃ ∙ ram iti hutabhujaṃ vaṃ jalaṃ maṇḍalaṃ tat ∙
laṃ kāraṃ bhūmisaṃjñaṃ ∙ tadupari mam idaṃ merusaṃjñaṃ tadurdhvaṃ ||
prajñopāyātmakaṃ kṣaṃ ∙ ham iti gaganataḥ śūnyanairaṃjanīyaṃ ∙
kūṭaṃ saptākṣarīyaṃ ∙ praṇamata satataṃ ∙ vajrapātādyahārīṃ || 1 ||
“The letter ya is what we call the air, ra is fire, va is water: the circle we call earth is the letter la, on it ma is what is called Mount Meru, above the latter is kṣa, which has the nature of the means to wisdom; from ha, the sky, is the spotless purity that is emptiness. This seven-letter diagram is [such a] group: bow incessantly to this excellent one that wards off the fall of thunderbolt!”