Many applets about many aspects of crystallography
(atomic formfactor curves, quasiperiodic tiling, stereograms, Lauegrams,
Fourier transform etc. etc.)
Subjects: Experimental setup, Structure factors (interactive!),
Phasing Techniques, ...
from the author: [...] my web tutorial which let you calculate structure factors,
Fourier synthesis and Patterson functions for simple structures you can
enter yourself. Things like breakdown of Friedel's law due to anomalous
contributions, effects of cell size, resolution, centrosymmetry,
Fourier artefacts etc. can be explored.