Visual demonstration for matrix test showing a simple test. This was a live demo in which the participant was prompted to click the purple square with white vertical bar.

This resource can be downloaded or viewed using the link: mat_inst2.png

If you have wget available (typically on linux systems), then you can also obtain a copy using the command

 wget  -nd  biobank.ndph.ox.ac.uk/ukb/ukb/images/mat_inst2.png