Mathematica Note MathWorld is one of the world's largest online mathematical encyclopedias, and it is supported as a public service by Wolfram Research. (Which also supports this website.) Before I built the periodic table table I made a Triangle Table which contains an inlaid geometrical construction for the Spieker Center. Don't know what the Spieker Center is? Just click the handy link and MathWorld will tell you all about it, as it told me before I built the table.