Grandmother’s growth
“old girl’s head went through the ceiling as though it were butter.”
This simile, comparing Grandmother’s head to “butter” can be a reference to the fact that George does not think highly of her intellect. Her mind is like “butter” in George’s opinion, and therefore portrays her as being soft in the head and dim witted.
Potion-making
The potion is perhaps a representation of children’s creativity. Children are often cautious and tend to make up their own concoctions as children. However, we often underestimate the significance of the things they create, but Dahl is highlighting that children have far more potential in their ideas and creations than we give them credit for.
