The puzzle photo seems to show the prototype which went by the name of Junak B21.
You've earned the point, but I believe the vehicle shown in your image is also a Junak B21 prototype.
Manufacturer: SFM Szczecin
Motorcycle brand: Junak
Motorcycle models: M05, M06, M07, M10, etc.
Designation for three-wheeled version with front-mounted cargo box: B21
The first B21 prototype was built on a Junak model M07 motorcycle (circa 1958); the second prototype was built by transferring the same cargo box onto a Junak model M10 (circa 1963). A number of online sources have confused these two, but the underlying motorcycles can be distinguished by the size and design of the rear brake drum.
Now here's where it gets messy. While I intended this puzzle to feature the M07 B21 prototype, I've just realized that I inadvertently posted images of both prototypes!
The bottom puzzle image (gte388a) shows the 1958 Junak M07 B21 prototype, but the vehicle in the upper images (gte388) is the 1963 M10 B21 prototype (and I believe your image shows a modified version of the M10 B21 prototype).
So, while I was looking for you to specify 'Junak
M07 B21 prototype', simply identifying the collective images as 'Junak B21 prototype' was enough to earn you the point.
