Smuggler's Code

Smuggler's Code is a subset of Thieves' Cant that relies on symbols that are carved, painted, or woven onto walls and signs visible to fellow smugglers.
Many symbols of Smuggler's Code are based on Elvish runes, particularly in the wood elven dialects. The reason for this is twofold: both because of the code's history in Elvish whiskey runners, and because the Elvish language is denser in meaning than most other languages. Similar smugglers' codes have existed across history, but the system of symbols most widely known as Smuggler's Code became popular during the Volian Revolution in the early-to-mid-Y900s.
Codes are scrawled in discrete places with whatever writing implement is available: chalk, coal, mud, a dagger or nail, or even a sharp rock. Less commonly, they are displayed in quilts or tapestries in the windows of safehouses and other friendly establishments. Common symbols include marking the hulls and docks of boats willing to accept a smuggler (and whether or not they'll charge a fee to do so), marking safe rest stops and places particularly frequented by (or ignored by) the town guard, and designating taverns and other establishments open to purchasing from smugglers. A variation of smuggler's code also spread within the prison systems of the Aquatic Kingdoms and the Liberty Coast during the Y900-1000s, focused primarily on helping guide potential escapees to freedom.