Recently, a new source of data with great potential for use in the mathematics classroom has become available. The smartphones in our pockets are packed with sensors. Most phones have at a minimum global positioning, accelerometer, magnetometer, and gyroscope sensors. We give an example of the collection and analysis of global positioning sensor…

A technique discovered in 1939 can be used to build a device that is driven by standard circular motion (as in a drill press) and drills exact square holes. This device is quite different from the classic design by Watts, which uses a Reuleaux triangle and drills a hole that is almost, but not exactly, square. We describe the device in detail,…