Foremost, James Forms are abstract. They do not look like trees or houses although all can be embellished to look like familiar objects at the risk of introducing accidental features.
They do look like some familiar objects such as boxes and floor plans, however the containment relations do not resemble natural containment processes such as putting lettuce into a Bag and then putting the bag into a shopping cart or putting pots into the cupboard of the kitchen in a house.
~
Bricken, Iconic Arithmetic Volume III: The Structure of Imaginary And Infinite Forms, p. 355–356.