I had noticed the little arrows scribbled on the mattress a long time ago but never asked why. After all, I've got my own quirks so who am I to judge.
Then Stuart recently told me that there are four arrows, two on each side of the mattress, at opposite corners, one ponting up and one pointing sideways. And that every time I change the sheets I was meant to turn the mattress in the direction of the arrow at the foot of the bed, so that in the long run both sides and both surfaces of the mattress get used evenly.
Like I was going to guess that by myself.
But things seemed to pick up on the way to work as I beat my PB (never went above level 100 before) - see pic #2. And this is the reason I stopped reading.
And then the sun was shining most of today, and when I got home I could still see shadows on the walls - pic #3.