http://gdea.informatik.uni-koeln.de/731/ On Straightening Low-Diameter Unit Trees A polygonal chain is a sequence of consecutively joined edges embedded in space. A k-chain is a chain of k edges. A polygonal tree is a set of edges joined into a tree structure embedded in space. A unit tree is a tree with only edges of unit lenght. A chain or a tree is simple if non-adjacent edges do not intersect. ... Poon, Sheung-Hung Z.999 On Straightening Low-Diameter Unit Trees 2006-03-15 Poon, Sheung-Hung (2006) On Straightening Low-Diameter Unit Trees. [Conference Poster] Healy, Patrick Nikolov, Nikola S.