Morse Code

Morse Code is a character encoding scheme that encodes written texts into dots (short) and dashes (long).

The Blood of Olympus
After infiltrating Ithaca, Annabeth Chase flashes a message to Leo Valdez on the Argo II to inform him that Jason Grace is hurt and needs medical attention and to send Frank Zhang to help take him back.

Users

 * Annabeth Chase
 * Leo Valdez