A symbolic expression formatted as a tree:

Show the tree form for the first two levels in the expression:

A graphics expression formatted as a tree:

A formatted symbolic expression with mathematical constants:

A formatted expression with symbolic, exact and inexact values:

A nested list:

An expression containing subscripted variables:

A formatted expression with a special superscript and OverBar:

A graphic object:

A Series expression:

An expression containing Hold:

Limit the levels shown:

Visualize the Wolfram Axiom for Boolean algebra as a tree:

FullForm gives a linear expression similar to TreeForm:

OutputForm of TreeForm gives a textual display of the expression:

Use TreePlot to plot a tree graph:

Use GraphPlot or GraphPlot3D for general undirected graphs:

Use LayeredGraphPlot for hierarchical-style drawing of directed graphs:

The typeset form of TreeForm[expr] is interpreted the same as expr when used in input:

Copy the output and paste it into an input cell. The is interpreted as x²:

When an input evaluates to TreeForm[expr], TreeForm does not appear in the output:

Out is assigned the value x², not TreeForm[x^2]:

Compound heads are not laid out as trees:

Even when an output omits TreeForm from the top level, it is not stripped from subexpressions:

The output does not have TreeForm in it:

However, the variable e does have TreeForm in it, which may affect subsequent evaluations:

The product is not evaluated due to the intervening TreeForm:

Assign variables first and then apply TreeForm to the result to maintain computability:

A complete binary tree:

A complete ternary tree:

A symmetric tree:

An asymmetric tree: