 Aβ proteins form antiparallel β sheets which are strongly amphiphilic, and which aggregate to form toxic oxidative Aβ fibrils.Aβ fibrils themselves are composed of amphiphilic 13-mer modular β sandwiches separated by reverse turns.Hydropathic waves optimize the description of the small (40,42 aa) plaque-forming (aggregative) Aβ fragments.