Using Lisp Syntax to Express Trees

Lisp syntax is nice for expressing tree structure in linear text. A Lisp expression has the form

  expr = (functionName expr1 expr2 ... exprN)

where functionName names a function (analogous to a procedure or subroutine in other languages), and expr1...exprN are the $N$ function arguments, each of which is a Lisp expression itself. So, in Lisp, an example three-level tree consisting of one parent, two children, and five grandchildren, could look like

tree = (topNode 
         (leftChild 
           (leftLeftGrandChild leftMiddleGrandChild leftRightGrandChild))
         (rightChild 
           (rightLeftGrandChild rightRightGrandChild)))