The red wool indicates the focal plane. Mamiya 80mm Macro at f/4.
The near-side of the red Transit and the front frille of the green SAAB are in focus. The Euclid lorry is beyond the plane of focus.
Place the focal plane along the near-side of the Euclid. Part of the front-right wing of the SAAB is just within focus.
Place the focal plane perpendicular to the chassis of the Euclid; only part of the cab is in focus. The focal plane also intersects the rear body of the Transit but the SAAB is completely out. I only noticed later that I had bumped the Transit slightly and knocked it out of alignment with the other photos.