Cross polarisation

One of the demonstrations at last night's camera club meeting was cross-polarisation:  using polarised light (from a laptop screen) and a polariser on the camera to view the stress patterns in materials.  I have done this in the past, but I decided to have another go today.  The difference - inspired by last night's demonstration - was to view it through a glass sphere. The patterns viewed through the sphere are created by a sheet of plastic wrapping material.  However, the more interesting patterns are in the plastic base supporting the glass ball!

I didn't spend a lot of time on this, and it probably shows.  Certainly the results are not as creative as Lesley Alsford achieved last night at the club.