Bee Battleships

Went to inspect the hives yesterday, but before I did, I drew a grid on the varroa boards as I will do a seven-day varroa drop count to see whether I need to do anything before winter.
Once again preparation would have paid off, as I used my trusty permanent marker, that has helped through many a permanently marking situation. Obviously too often, as the pen ran out as I was drawing the lines. It just about held, but the lines are very faint. I will have to redraw them with a fresh pen. I also labelled the columns with letters and the rows with numbers, so if the bees get bored (no pun intended), they can play varroa battleships, or similar.

Oh, and I did have photos of all this, but my computer swallowed them without a trace, so unfortunately there are none. I will try to take some of one board when I'm next out there. Sorry...

This is the board after it's been in a few days. As you can see, the bees have already started playing battleships and there's a wasp sunk in A5.