The Lattice QCD science output comes from applications packages (yellow plaquettes) which provide a
context in which the underlying SciDAC modules can perform their work. Level 1, Level 2, and Level 3 packages can be built independently of the applications and used in your own codes if you wish. However, please heed this warning:
Given the number of modules and the combinatorically larger variety of possible ways to combine them, we suggest that if you are new to this game you can save yourself a lot of frustration by checking out one of the application suites.