1. Define the instance variables for a new generic node implementation that could be used for a tree in which each node has up to four children and each node also has a reference to its parent. Store...

1. Define the instance variables for a new generic node implementation that could be used for a tree in which each node has up to four children and each node also has a reference to its parent. Store the references to the children in an array of four references to nodes.

2. Implement the learn method from the animal-guessing program.