Photo — Swap collage
Two photographs split the frame but trade places: each half wears the other's blow-up while mirrored windows swap the missing patches back.
The canvas is halved and the pair crossed — one half filled with the other photo enlarged, and vice versa. A rectangle sits on each half at mirrored positions, and through it shows a patch belonging to the opposite side, so the two windows literally exchange what they cover. Clicking re-seats both windows at once, and the blow-ups swell slowly as each pair's turn elapses.
The exchange is exact rather than decorative: each window samples precisely the region of the opposite half's background that its twin hides, through the same cover-crop mapping, so edges line up when a window hugs the seam. Photos are consumed in fixed pairs — first with second, third with fourth — each pair holding the frame for an equal share of the loop.
