Got into a working rhythm with this today. Rubble and earth and roots and God knows what else is piled up on what I was calling 'old greenhouse foundations', East of the path. That's where I first planted anything on the plot, borage and phacelia. It's a mixture of bricks and half bricks and bigger bits of concrete, which take a role in the skinny boundary path. Smaller rubble goes across the path into the New Potting Shed's foundations.
There's a lot of earth mixed through it. Today is the first day I've used the riddle in earnest. One shovelful of earth/rubble is just right for the hand riddle you can see in the photo. Good abdominal exercise, if the whole plot is to get riddled eventually, I'll be swapping the beer belly for a six-pack. Really feel like I've gotten to know the plot's earth, doing this. For example, you can see in the riddle there's a great deal of "gravel", bits of stone about 1cm3.
The riddled earth I'm piling up, ready for the raised beds.