Lazy Evaluation
  Understand functions like map, filter, and iterate that return lazy 
sequences. Be able to use them to compute with lazy sequences.
  Understand how to use lazy-seq, and issues involving sequence 
realization and memoization

Concurrency
  Understand Refs, Atoms, Agents, and Vars, the Snake example, and the Ant 
Colony example.

Macros
  Write a simple macro. Expand macros. 
  Be familiar with the support in Figure 7.1 and the classification in 
Figure 7.2

Multimethods
  Be able to define a multimethod and implementations.
  Use multimethods to create an ad hoc taxonomy.

Lancet
  Understand the Lancet code to instantiate an Ant task with properties 
included.
  Undestand how to create a runonce function that takes a function and 
returns a new function that will run only once.
  Understand the use of macros to make Lancet easier to use.
  Underatnd the use of multimethods to make Lancet easier to use.