Examples of perfectly four‐coordinated networks satisfying periodic boundary conditions are constructed by a pseudo‐random process, starting from a crystalline region. The unphysical features (high density, large deviations from the tetrahedral bond‐angle) are removed by systematic modification of the bonding scheme. The vibrational spectra are calculated, using a valence‐force potential, and the neutron scattering is computed by a phonon‐expansion approximation.