@alex It's taboo or blasphemy to draw The Holy Spirit or God The Father outside of iconography, and even that has its own rules and layers, although depictions of The Holy Spirit via a dove or flaming cross are common and widely accepted. One of the few times you'll see a depiction as a human is in the icon of Abraham Welcoming The Lord (Genesis 18:1-15), AKA "The Holy Trinity" icon.

>The guests are described simply as three men, but when Abraham talks to them, they respond as one ("they said"). The Lord appeared to Abraham, but when he looks to see who is there, he sees three men. Three men speaking as one; the one God in three persons: Father, Son and Holy Spirit. At other times, only one of the angels speaks to Abraham and he is referred to as "Lord." In the icon, it is most often felt that the angel in the center of the icon is the one referred to as Lord: Jesus Christ.