This week's Annunciation scene is an Orthodox icon. It shows many of the traditional elements of the Annunciation scene, with the angel greeting Mary, who has been spinning (see the spindle in her left hand), while a ray of light descends from God the Father in heaven.
The particular detail that I wanted to focus on in this depiction, however, is the gesture made by the angel as he greets Mary. Here is a detail that shows you the hand gesture he is making:
The thumb is touching the ring finger, leaving three fingers extended. This sign is called a "Christogram" because the fingers are actually spelling out four letters in Greek, I-C (I-S in the Roman alphabet), the first and last letters of the name "Jesus," and X-C (CH-S in the Roman alphabet), the first and last letters of the name "Christos" (Christ).
A finger extended straight shows the letter I, a finger extended but bent shows the letter C, the thumb crossed over the index finger is X, and a finger extended but bent shows the other C.
Here is an image that can help you see the pattern of the fingers more clearly:
Although the gesture is more closely associated with the Orthodox Church, you can also find the gesture depicted in Catholic art as well. The gesture is one that Orthodox priests still use today to extend a blessing. You can read more about that in this article about How to Greet an Orthodox Priest.
In addition to the I-C X-C Christogram, there is also a famous Christogram based on the first three letters of Jesus's name in Greek, I-H-C, which is sometimes partially Romanized as I-H-S or J-H-S, as you can see here (for more examples, see the Wikipedia article).
There is even some speculation that the oath "Jesus H. Christ" comes from a misreading of this Christogram, where the capital form of the Greek eta, H, is misread as a Roman letter H!
Finally, there is also a X-P Christogram, called the "Chi-Rho" Christogram, based on the first two letters of "Christ" (CH-R in the Roman alphabet). You can read more about the Chi-Rho Christograph in this Wikipedia article.
Although this is a very small detail in this depiction of the Annunciation, the details all contribute to the message which the icon conveys to its viewers. In this case, it is not the devil that is in the details - but the savior! You can find out more about this particular icon and its symbolism in this Annunciation article at the Greek Orthodox Archdiocese of America website.