A couple of weekends ago, after two years of this test-page nonsense, I thought: surely this must be fixable? Poor dad. I must try harder to fix it. So, up I went, turned on the printer, and it printed the test page. Which I then, for the first time in two years, actually looked at.
Turns out it’s not a test page at all. When you put new ink cartridges in the printer, it prints one of these pages and then you’re supposed to scan that same page; the printer uses it to re-align the printer heads, because it can see from the printout whether the lines are straight.
Nice post by Sil.