  A non-equilateral triangle in a Euclidean plane has exactly two isogonic and
two isodynamic points. There are a number of different but equivalent
characterizations of these triangle centers. The aim of this paper is to work
out characteristic properties of isogonic and isodynamic centers of simplices
that can be transferred to higher dimensions. In addition, a geometric
description of the Weiszfeld algorithm for calculating the Fermat point of a
simplex is given.
