OpenB@Chin-PalmBack OpenB@FromChin-PalmUp

Etymology
Possibly a compound of and the formal pronoun, thus meaning literally, “you, sir (or madam), are good”.

Production

 * Move the hand forward and down to the following posture.
 * Move the hand forward and down to the following posture.
 * Move the hand forward and down to the following posture.

Verb

 * 1)  to thank (someone)

Inflection

 * In the final posture of the sign, the hand is extended out toward the object (the recipient of the thanks).