This illustrates the symbol digit test. Participants were shown a series of similar screens until the time limit expired.

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

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

 wget  -nd  biobank.ctsu.ox.ac.uk/ukb/ukb/images/hm_symdig_real.png