Using the theory of plugs and the self-insertion construction due to the second
author, we prove that a foliation of any codimension of any manifold can be modified in a
real analytic or piecewise-linear fashion so that all minimal sets have codimension 1. In
particular, the 3-sphere S^3 has a real analytic dynamical system such that all limit sets
are 2-dimensional. We also prove that a 1-dimensional foliation of a manifold of dimension
at least 3 can be modified in a piecewise-linear fashion so that there are no closed leaves
but all minimal sets are 1-dimensional. These theorems provide new counterexamples to the
Seifert conjecture, which asserts that every dynamical system on S^3 with no singular
points has a periodic trajectory.