More from Chalkdust
On the cover: A new puzzle every day
Matthew Scroggs puts polyominoes inside polygons
Forest fires
Steven Lockwood finds polygonal numbers hidden in a spreading fire
Dog leads, mirrors and Hermann Minkowski
Donovan Young looks at the shapes made when two cones collide
Flo-maps fractograms: the prequel
Hugh Duncan returns with the long-awaited prequel in which he further explores the geometric patterns hidden behind the fractions.
Top Ten: Calculators
Are you a FX-82 or an FX-85 fan?
A counterintuitive result in the theory of traffic flow
Additional roads do not imply faster travel times!