Some depict hunters with bows, naked humans (though you rarely see the gender), some children (most carried or on the backs of others) and animals
Plato is pointing up to the heavens, signifying that everything is a reflection of Forms that resides in heaven.
What was specific about his painting technique was that he would always try to involve the viewer of the painting by drawing eyes and the positioning of his characters in such a way that it always seems as if they're maintaining eye contact with the audience. This was done using various perspectives and is kind of like an illusion, similarly to how the Mona Lisa is painted.
The first one can be seen either way. For me, I saw a vase first. In all of the pictures, the black drawing is considered the positive space and the white background behind it is considered to be the negative space. If you look at the vase picture again and imagine the background to be the black portion, you see two faces.
Hope this helps! :)
