  At the end of their lives low mass stars such as our Sun lose most of their
mass. The resulting planetary nebulae show a wide variety of shapes, from
spherical to highly bipolar. According to the generalized interacting stellar
winds model, these shapes are due to an interaction between a very fast tenuous
outflow, and a denser environment left over from an earlier slow phase of mass
loss. Previous analytical and numerical work shows that this mechanism can
explain cylindrically symmetric nebulae very well. However, many circumstellar
nebulae have a multipolar or point-symmetric shape. With two-dimensional
calculations, Icke showed that these seemingly enigmatic forms can be easily
reproduced by a two-wind model in which the confining disk is warped, as is
expected to occur in irradiated disks. Here, we present the extension to fully
three-dimensional adaptive mesh refinement simulations of such an interaction.
