Participants in the discussions were particularly unconvinced by a statement in the "Topological origin of inertia" paper that "whatever the orientation, the plane of oscillation of Foucault's pendulum is necessarily aligned with the initial singularity marking the origin of physical space." In addition, the paper claimed, the Foucault pendulum experiment "cannot be explained satisfactorily in either classical or relativistic mechanics". The physicists commenting on Usenet found these claims and subsequent attempts at their explanation peculiar, since the trajectory of a Foucault pendulum—a standard museum piece—is accurately predicted by classical mechanics. The Bogdanovs explained that these claims would only be clear in the context of topological field theory. Baez and Russell Blackadar attempted to determine the meaning of the "plane of oscillation" statement; after the Bogdanovs issued some elaborations, Baez concluded that it was a complicated way of rephrasing the following: