by scottlamb | 2025-11-20 15:43:17+00:00
The rollout doesn't seem to have reached my userid yet. How successful are people at getting these things to actually produce useful images? I was trying recently with the (non-Pro) Nano Banana to see what the fuss was about. As a test case, I tried to get it to make a diagram of a zipper merge (in driving), using numbered arrows to indicate what the first, second, third, etc. cars should do.

I had trouble reliably getting it to...

* produce just two lanes of traffic

* have all the cars facing the same way—sometimes even within one lane they'd be facing in opposite directions.

* contain the construction within the blocked-off area. I think similarly it wouldn't understand which side was supposed to be blocked off. It'd also put the lane closure sign in lanes that were supposed to be open.

* have the cars be in proportion to the lane and road instead of two side-by-side within a lane.

* have the arrows go in the correct direction instead of veering into the shoulder or U-turning back into oncoming traffic

* use each number once, much less on the correct car

This is consistent with my understanding of how LLMs work, but I don't understand how you can "visualize real-time information like weather or sports" accurately with these failings.

Below is one of the prompts I tried to go from scratch to an image:

> You are an illustrator for a drivers' education handbook. You are an expert on US road signage and traffic laws. We need to prepare a diagram of a "zipper merge". It should clearly show what drivers are expected to do, without distracting elements.

> First, draw two lanes representing a single direction of travel from the bottom to the top of the image (not an entire two-way road), with a dotted white line dividing them. Make sure there's enough space for the several car-lengths approaching a construction site. Include only the illustration; no title or legend.

> Add the construction in the right lane only near the top (far side). It should have the correct signage for lane closure and merging to the left as drivers approach a demolished section. The left lane should be clear. The sign should be in the closed lane or right shoulder.

> Add cars in the unclosed sections of the road. Each car should be almost as wide as its lane.

> Add numbered arrows #1–#5 indicating the next cars to pass to the left of the "lane closed" sign. They should be in the direction the cars will move: from the bottom of the illustration to the top. One car should proceed straight in the left lane, then one should merge from the right to the left (indicate this with a curved arrow), another should proceed straight in the left, another should merge, and so on.

I did have a bit better luck starting from a simple image and adding an element to it with each prompt. But on the other hand, when I did that it wouldn't do as well at keeping space for things. And sometimes it just didn't make any changes to the image at all. A lot of dead ends.

I also tried sketching myself and having it change the illustration style. But it didn't do it completely. It turned some of my boxes into cars but not necessarily all of them. It drew a "proper" lane divider over my thin dotted line but still kept the original line. etc.