Computer-aided Origami

Posted in Design, Fun links, Math by Mike Stay on 2008 February 26

With really cool bugs!

Touch-sensitive plant

Posted in Fun links by Mike Stay on 2008 February 26

Mimosa pudica — this stuff was all over the place in Guatemala.  The tender leaves fold up, drop down, and expose lots of thorns.

A most excellent gentleman

Posted in Fun links, Time by Mike Stay on 2008 February 26

Passive polarization clock

Posted in Astronomy, Math, Time by Mike Stay on 2008 February 22

Here’s a design for a passive polarization clock.

The sky is polarized in concentric circles around the sun. The polarization of the southern sky moves through around 180 degrees during daylight hours. It is polarized vertically in the morning, horizontally at noon, and vertically again in the evening.

Align slices of polarized film such that they are parallel to the contours. Any given ray from the center of the sundial outward always hits the contours at the same angle; the angle changes by 360 degrees as the ray passes through 180 degrees. In other words, the clock goes from 6am to 6pm as the sun moves through the sky.