is a video of a game which replicates Portal's physics system in 2 dimensions on the TI-83 graphic calculator. The game
was developed by a 20 year old student studying game design. A download link is available here
solves over 100 different equations online.
Find the distance between two American telephone exchanges with the Interoffice Mileage Calculator
. Find the distance between any two cities in the world with How Far Is It?
. The latter also has a full database of American and Canadian towns, so I know that my hometown is 4864 miles from Athens, Greece, and 768 miles from Athens, Georgia.