  Using the authors' 2014 "constraints method," we give a short proof for a
2015 result of Dobbins on representations of a point in a polytope as the
barycenter of points in a skeleton, and show that the "r-fold Whitney trick" of
Mabillard and Wagner (2014/2015) implies that the Topological Tverberg
Conjecture for r-fold intersections fails dramatically for all r that are not
prime powers.
