Piano-hinged Dissections: Time to Fold!

by Greg Frederickson

Adjusting the display for the Video Demonstrations:

It would be wonderful if we could just pop the CD for the video demonstrations into the CD reader and have everything play perfectly. However, that presumes that there is a universally accepted standard for video playback, which apparently there isn't. Although my CD works fine on some computers, I found that on others the horizontal dimension can appear to be stretched by a small amount relative to the vertical dimension. I noticed this problem on Macs that use Quicktime, machines running Linux, and even some Windows machines.
Maybe most readers won't be bothered by the distortion, but I was, so I found ways to adjust the viewers so that a square really does look like a square in the videos. You can test how well your machine does by viewing the squares (in "Two squares to one") at the beginning of the video segment that demonstrates the wooden models.
If you are viewing the videos on a Mac using Quicktime, you can adjust the playback window as follows: To change the playback size (but not change the horizontal to vertical ratio), drag the resize control in the lower-right corner of the window. To stretch either horizontal or vertical dimension relative to the other, hold down the shift key while you drag.
If you are viewing the videos on a machine installed with Linux, you can adjust the Totem Media Player as follows: Click on the pull-down menu "View", then click on "Aspect Ratio", and finally click on "4/3 (television)".
If you are viewing the videos on a Windows machine, you can adjust Media Player as follows: In the upper-right corner, identify the "down arrow" (the fourth symbol to the left from that corner). Click on the down arrow, then click on "Tools", then click on "Options", then click on "Devices", then click on "Display", then click on "Properties". This then gives you a field in which to set the number of horizontal pixels per vertical pixel. For one Dell machine that I tried, in which the horizontal dimension was stretched relative to the vertical dimension, I found that setting that field to 1.118 seemed to work well.