Despite of the apparent complexity of the topology optimization method it can actually be programmed in surprisingly few lines of code. For example, if using a high level programming language like Matlab, the code for solving the basic compliance minimization problem discussed in Chap. 1 may be written in only 99 lines (Sigmund 2001a). In this appendix we first discuss the Matlab implementation of the minimum compliance problem in some detail (based on Sigmund (2001a)). Afterwards, we briefly discuss the extensions of the code to a 105-line compliant mechanism synthesis code and a 91-line code for topology optimization of conductivity problems.