The legend appears to be an invocation, but the square is a Yantra or a Chakra.
The specific number 34 belongs to Sri Rama Chakra that was very popular among common man until recently.
We can see it produced in the Panchagas (Fig:1) along with Seeta Chakra.
When someone is in distress and clueless about what is in store, he will touch one of the squares with eyes closed and after a prayer to Sri Rama.
Each number indicates a result.
The totalling differs from deity to deity.
For example, a similar Yantra is worshiped in the Lakshmi sannidhi of Thirunindravur near Chennai (Fig:2)
The total is 72 (7+2= 9)
Devotees can get a miniature yantra in the temple for worship at home for wealth.
The Navagraha yantras also have such magic squares but differ from each other in the final total. (Fig:3)
These numbers are unique to each graha / deity. Navagraha yantras differ from the above two by being made on specific geometric designs, whereas Sri Rama Chakra, Seeta Chakra and Lakshmi Chakra are just squares.
Soma Yantra -like golden plate was found worn by a Druid buried 4000 years ago in Bush Barrow in the UK (Fig: 4)
Crux of the matter is, these squares are many, designed with specific numbers that signify a deity. Number 34 ending squares were used by common man for ages.
Regards,
Jayasree Saranathan