  We propose a new method for computing the lasso path, using the fact that the
Manhattan norm of the coefficient vector is linear over every orthant of the
parameter space. We use simple calculus and present an algorithm in which the
lasso path is series of orthant moves. Our proposal gives the same results as
standard literature, with the advantage of neat interpretation of results and
explicit lasso formul{\ae}. We extend this proposal to elastic nets and obtain
explicit, exact formul{\ae} for the elastic net path, and with a simple change,
our lasso algorithm can be used for elastic nets. We present computational
examples and provide simple R prototype code.
