  The Zeldovich approximation (ZA) predicts the formation of a web of
singularities. While these singularities may only exist in the most formal
interpretation of the ZA, they provide a powerful tool for the analysis of
initial conditions. We present a novel method to find the skeleton of the
resulting cosmic web based on singularities in the primordial deformation
tensor and its higher order derivatives. We show that the A_3-lines predict the
formation of filaments in a two-dimensional model. We continue with
applications of the adhesion model to visualise structures in the local (z <
0.03) universe.
