You've seen the image. A tree split down the middle - winter on the left, summer on the right. It's on calendars, insurance ads, and every "four seasons" poster in every dentist's waiting room. It's the most obvious impossible-photograph concept there is.

So I tested it. Six variations. Twenty-four images. And the obvious approach was the worst one.

I started where everyone starts:

The problem isn't that Firefly can't do it - it's that Firefly has already seen this exact concept thousands of times. It didn't construct an impossible scene. It reproduced a design template.

I tried a gradient blend next. Same tree, same seasons, but "transitioning from... gradually blending into" instead of "split perfectly down the middle." It scored 7.44. Better - the ground transition softened nicely, snow fading through a misty zone into grass. But the tree canopy still switched abruptly from bare to leafed because branch foliage is categorical: leaves are either there or they aren't. You can gradient a ground surface. You can't gradient a branch.

This is where every principle I've learned in four sessions of testing told me I was making a mistake. Across Parts 1 through 4, I'd proven that constrained impossibility outperforms unbounded impossibility. One impossible element, not three. One floating object type, not five. Simpler is better.

So four seasons should score lower than two. More complexity, more ways to fail.

It scored 8.72 average. The session's highest by over a point.

I spent a while staring at the images before I understood what happened. The constrained impossibility principle is about physics violations, not visual elements. A tree in four seasons isn't four impossibilities - it's one impossibility (seasons can't coexist) expressed in four colors. Two seasons have grey and green. Four seasons have pink, green, orange, and white - all rendered in golden hour warmth.

The additional seasons didn't make the image more complex. They made it more beautiful.

But the golden hour lighting is the real discovery. In the two-season splits, the sky changed from grey overcast to bright blue - different lighting on each side. That split lighting amplified the composite feel. Each half of the image was a different photograph with different ambient light.

The four-season tree bathes everything in the same golden hour warmth. All four seasons share one light source. That unified lighting is what makes four seasons feel like one photograph instead of four photographs merged. The golden hour doesn't pick a season - it illuminates all of them equally, and the viewer's eye accepts the impossibility because the light says "this is one moment, one place."

The second-highest-scoring variation wasn't a tree at all. It was a country road.

This scored 8.34 average. The trick is using depth instead of left-right as the transition axis. The road surface transitions from fallen leaves to light frost. And atmospheric haze creates the boundary - the seasons don't meet at a line, they meet at a distance.

This works because foreground-to-background change is how cameras naturally see the world. Close things are one way, far things are another, and the middle is ambiguous. Left-right splits never occur in nature. Depth transitions happen every day.

The atmospheric haze is the mechanism that makes depth work. Without it, foreground autumn and background winter would feel like two layers. With it, the change feels like distance - the seasons are different because you're looking further into the landscape. I've seen this same principle across all four previous sessions: atmospheric haze makes impossible spatial relationships feel photographically real whether you're selling giant scale, selective gravity, or seasonal collision.

The surprise second-place finisher was the architectural variation - a Victorian house with summer on one side and winter on the other.

This scored 8.46 average - higher than the gradient tree, the depth landscape, and the bench scene. It beat the same left-right split concept that scored 7.17 on a tree.

Why? Buildings provide structural coherence that trees can't. A tree IS the environment you're trying to split - so splitting it feels like splitting the subject. A building EXISTS IN the environment - so splitting the environment around it feels more natural. The house stands unchanged while the world around it transforms. That's a more compelling impossibility.

The warm/cool color temperature split helped too. Firefly understood that seasons don't just change what's on the ground - they change the quality of light hitting everything.

One more result worth noting. I prompted a park bench at the boundary between autumn and winter, with "single fallen leaf caught mid-air on the boundary line."

This is the kind of small, concrete, poetic detail that Firefly handles reliably when you name it specifically - the same way "oil droplets between gear teeth" worked in Part 2 and "dust particles in light beam" worked in Part 3. Specific, small-scale detail instructions land.

And the bench itself adds something the tree and road don't: emotional narrative. A bench implies a person who isn't there. Someone sat at this exact spot and watched autumn end. That emotional resonance is why human-scale objects (benches, houses, roads) outperform pure landscape subjects for this concept.

Six variations gave me a clear hierarchy for seasonal collision in Firefly:

Use golden hour lighting. Unified warm light makes impossible scenes feel like single photographs. Split lighting (grey sky vs. blue sky) amplifies the composite feel.

Use depth, not left-right. Foreground-to-background seasonal change aligns with natural visual perception. Left-right splits are artificial constructs that read as composites.

Use adjacent seasons. Autumn-to-winter (8.34 avg) outperforms winter-to-summer (7.17 avg) by more than a point. Adjacent seasons have smaller visual gaps, making transitions more plausible.

Use buildings or human-scale objects, not bare trees. Buildings provide structural coherence and imply human experience. Benches add emotional narrative. Trees in isolation are the weakest subject for this concept because you're splitting the subject itself rather than splitting the environment around it.

Don't fear four seasons. More colors with unified lighting outperforms fewer colors with split lighting. The constrained impossibility principle applies to physics violations, not to the color palette.

Avoid the calendar design. If your prompt would produce a Stock composite that an insurance company would use, push further. The familiar version of this concept is the weakest version.

24 images. 6 approaches. The calendar design was last. The one I expected to fail was first.

Sometimes the data surprises you. That's why you test.

Testing methodology: All images generated in Adobe Firefly Image 5, single session. Each variation generated 4 images. Scored on a 5-dimension rubric: Visual Quality (30%), Prompt Alignment (25%), Consistency (15%), Uniqueness (15%), X Engagement Potential (15%). No cherry-picking - all images scored, averages reported.