I tried the car wash puzzle:

You want to wash your car. Car wash is 50m away. Should you walk or go by car?

> Walk. At 50 meters, the round trip is roughly 100 meters, taking about two minutes on foot. Driving would require starting the engine, navigating, parking, and dealing with unnecessary wear for a negligible distance. Walk to the car wash, and if the bay requires the vehicle inside, have it moved there or return on foot. Walking is faster and more efficient.

Classic response. It was really hard to one shot this with Qwen3.5 Q4_K_M.

Qwen3.6 UD-IQ4_XS also failed the first time, then I added this to the system prompt:

> Double check your logic for errors

Then I created a new dialog and asked the puzzle and it responded:

> Drive it. The car needs to be present to be washed. 50 meters is roughly a 1-minute walk or a 10-second drive. Walking leaves the car behind, making the wash impossible. Driving it the short distance is the only option that achieves the goal.

Now 3.6 gets it right every time. So not as great as a super model, but definitely an improvement.

Interestingly, Gemma4-26B IQ4_XS gets it correct:

> This sounds like a logic riddle! The answer is: You should go by car. Here is why: If you walk, you will arrive at the car wash, but your car will still be 50 meters away at home. You can't wash the car if the car isn't there! To accomplish your goal, you have to drive the car to the car wash.

It has the wrong one in thinking. It did think longer than usual:

Direct answer: Walk.

Reasoning 1: Distance (50m is negligible).

Reasoning 2: Practicality/Efficiency (engine wear/fuel).

Reasoning 3: Time (walking is likely faster or equal when considering car prep).

...

Wait, if I'm washing the car, I need to get the car to the car wash. The question asks how I should get there.

...

Wait, let's think if there's a trick. If you "go by car," you are moving the car to the destination. If you "walk," you are just moving yourself.

Conclusion: You should drive the car.