Tesla appears to be running its electric semi tractor through its paces after photos of two examples were photographed on trailers in separate parts of the country.

The first was spotted near Louisville, Kentucky and posted to Twitter by @KentuckyToc, and first noticed by Teslarati. The damaged truck appears to have been undergoing testing, perhaps on a runaway ramp, since the pieces of gravel can be spotted lodged between the headlight and the body panel.

Intriguingly, Tesla was careful not to show the interior of the vehicle and actually taped plastic sheeting to the inside of the windows to prevent onlookers from catching a glimpse inside the Semi.

Read Also: The First Tesla Semi Trucks Will Be Delivered This Year, Says Elon Musk

The second truck, (whose manufacturer’s license plate reads 63277 34P, rather than the first truck’s 63277 23M) was spotted by Reddit user u/helloiisjason off the I-10 in Arizona on its way to Tesla’s gigafactory in Texas. Also being trailered, this model featured tape over the trim on the A-pillar which was missing on the first truck.

Its interior has not, however, been hidden from view, and its steering wheel can be seen through the windshield. Much farther forward than the door, it will be interesting to see the layout of the cabin, which must give drivers a good view of the road.

Both similar in design to the new images of the Tesla Semi recently posted by the company, they feature the elongated black section that extends behind the doors. That design cue was not present in the original renderings of the truck. Both also have a black roof that does not extend all the way back, seemingly exposing some of the cab’s structural elements. That may indicate that these pre-production examples are not yet 100 percent true to production.

First announced in 2017, the Tesla Semi was supposed to be on the road in 2019, but after countless delays has not yet reached production. In August, the automaker’s CEO, Elon Musk, claimed that the “Tesla 500 mile range Semi Truck starts shipping this year,” though his estimates have not always been accurate.

Although the company is accepting $20,000 deposits, the final specifications of the production version have not yet been confirmed. These photos, though, are a sign of life and suggest that a production version may actually be trundling towards reality.

Lead image KentuckyToc/Twitter