My sons would say, "Weird Dad". The trick is, not to read it too closely, just rapidly scan the lines, and read as fast as you can, once you get going it becomes very easy, everything falls into place, maybe faster than speed reading, however I have never tried speed reading so am unable to judge.
I used to receive emails like that from a soldier in the same Infantry regiment and Company I also served in during WW2, sadly he passed away a few months ago. I believe they were to test for Altimer (sp?) age related, or other disorders. I don't know who originated the tests. One test was where say 12 or so lines of 9s are displayed, and the test was see how long one took to find a 6 in the group without using any aid, say courser or pointer, another was the same layout with Os and a C planted in the group, also the same for other figures or numbers. I could spot them in a number of seconds, I put it down for having to read prints and drawings in steel fabricating and like industries for most of my working life, plus machine drawing at 13 years of age in a technical school in the UK.