rectangles of width 2 and height sqrt(3) laid in the bricklayer pattern have centers coinciding with centers of the regular hexagon tiling.  each rectangle is a flattened hexagon.perhaps useful for games normally played on a hexagonal tiling.

collisions in hash functions are unavoidable.  if you find one collision (messages A and B have the same hash), how easy is it to manufacture another collision (messages C and D have the same hash), or even an infinite collection of collisions? can cryptographic hash functions be designed to prevent collisions from easily yielding more collisions?

on official diagrams, the MBTA Red Line is drawn to split into the Ashmont and Braintree lines south of JFK/UMass station.  in reality, the lines have already split north of the station, and the station has separate platforms for each line.  to catch the next northbound (inbound) train, you have to guess which platform to wait on.  there is technology...

one of the few places that multiples of 10 exist in U.S. customary units is obscure units of area: 10 square chain = acre 10 acre = square furlong however, this feels awkward because 10 congruent squares cannot be arranged into a larger square.  it would have been nice if our counting system were based on a square number. acre is a square with...

Arlington is the town where people "arl". Birmingham is the ham (old French for "village") where people "birm".no one knows what those words mean, so invent something: having lived in Arlington, I can confirm that people there arl, a lot.  I will never forget the looks on the faces of those gerbils.

prove that spherically symmetric redistributions of mass do not emit gravitational waves.   (you are smarter than Einstein.)