The lines on the sheet going from left to right show the track of the sun for every day in a six month period (in this case from 22 December 2011 to 21 June 2012). The pairs of lines are weekends: these are blue for even months and red for odd ones.
The point of the shadow here converges on a Monday - the second Monday in May, giving a date of 14th May (see the detail below). The time one may read from the lines going the other way: 5:25pm. If the Sun Clock is set up correctly, the time should be accurate to the nearest minute. Whether the date can be read accurately depends on the time of year, as the lines bunch together as one approaches the solstices (late June and late December).
The thick black line marks the clock change: the times above in black give the times before the change, and the times in red below give the times after it. A new laminated sheet will be needed once a year, as an extra six months can be obtained by reversing the sheet.
The dial sheet is customised to the location and orientation of the plate and is produced using bespoke software on the Windows platform. A pair of sun clocks on southeast and southwest facing walls will cover the whole day. This is not currently a commercial product, but if you are a hobbyist interested in having your own (at cost) please contact the inventor Chris Oakley at c6goakle9y@virg3inmedi6a.com (NB: remove the numbers).