Align the two apples so they’re off center to one another. One has 2/3 on the outside to the left, 1/3 to the right, the other 2/3 to the outside to the right, 1/3 to the left.
Bird’s eye view, the single line cutting both apples will leave us with the left 2/3 of the first apple and the right 2/3 of the second, and a third portions made of 2 thirds, or another 2/3 of an apple.
One cut, 2 apples, 3 equal portions.
No need to align them like that. Just place them one behind the other and cut off one third on the side (with a single stroke).
You’re right that they’re off-center from a first “symmetry line” you have to draw.
So: you place them on your cutting board. Trace an imaginary vertical bird’s eye view that passes by the center of both. Now based on that imaginary line, move both apples so they’re offset 2/3-1/3 from that line in each direction.
I thought about this at first but then two people get the core as part of their portion and one doesn’t :(
