chicken-and-egg situation

autoresonance brush dam chippings choroid plexus of third ventricle compress technique Coulomb field ex-librist high-gain oscilloscope margo volaris Murray-convex machine neothoracaphis saramaoensis norphen plagioclase roll motion single-business strategy tat-tat theory of the second best trading service product wring sth out of zenithal equidistant map