No more halos on evergreens

[meds4sale]

FORM: Crystal
SENDER: The Medicine Seller
RECIPIENT: Everyone
WHAT: Peculiar questions about architecture to alleviate the boredom of quarantine time
WHEN: Recent
WHERE: Gallows
NOTES: None

During my time here before, I noticed a ... quirk of the older architecture in the city.

Grooves within the walls that did not seem ornamental. My companion had remarked that they reminded him of a sword's fuller, and given the history of this place, he may have been on to something.

The search for answers to this puzzle turned up many, many places where Kirkwall's underworld prefers to stash contraband and other less savory things. However, nothing in regard to this irregularity.

Perhaps someone may shed light on this? Or point me to whatever texts may likewise do so. The more obvious sources make no remark on it.

[There is a pause for a long period - that seemingly being the extent of his inquiry. And then he speaks again]

I am also curious about Thedosian purification rituals. Where I am from salt and water and, occasionally, ash are used to temporarily ward malevolent spirits. I am interested to see if such similarities persist here as well, or what the differences might be.