El Greco Easter Egg - Sticky Fingers

In every painting El Greco made he has at least one person's hand holding their middle and ring fingers together

(thumb) (index) (middle)(ring) (pinky)

this is best seen in his self portait

This became so popular during his time that it was passed on to other paintings, the most know are those of Jesus holding one of his hands over his thorned heart in this same manner.