SIGNS OF SATAN,

The following is an excerpt from the "Satanic Bible"...

Horned Hand or The Mano Cornuto:

This gesture is the Satanic salute, a sign of recognition between and allegiance of members of Satanism or other unholy groups.

Signs Of Satan! (12 minute video)

Note: As you can see, The Satanic Bible plainly evidences that the hand-sign showing allegiance to Satan can be flashed with either the thumb extended or concealed.