There are obvious and more subtle symbols in Saki's sardonic story on the vulnerability of people. Here are three:
1-2. The open window is the most obvious symbol as well as the most important. For, it provides the framework, literally and symbolically, for Vera's tall-tale that so frightens the timorous Framton Nuttel. (1) The fact that the window is open deceptively symbolizes the emptiness of Mrs. Stappleton's life and her hopelessness.
"Out through that window, three years ago to a day, her husband and her two young borther went of for their day's shooting. They never came back.
(2) It also symbolizes honesty and spiritual openness, allowing Vera to spin a deceptively fantastic lie about her relatives being dead when, in fact, they are alive.
3. Vera's name is also symbolic of her deception as it is a Latin form of the word veritas, which means truth. Thus, her name acts as another smokescreen for her deceptive tale. After the terrified Nuttel flees when the supposedly dead male Sappletons walk through the French doors/window and Vera offers another fabricated explanation to her aunt, Saki, who satirized the Ewardians of his age, adds sardonically, "Romance at short notice was her specialty."
4, Another thing that may be considered a symbol is the bog since Vera tells Framton Nuttel that Mrs. Sappleton's family "were all three engulfed in a treacherous piece of bog." Here the word bog can symbolize Vera's falseness intended to "bog" Nuttel down in her tall-tale, preventing him from perceiving the truth.