<|im_start|>user
How many prototypes were made?

Context:
The first prototype was entirely mechanical. Three prototypes were made, and they were improved over one year. In the meantime, sure of having found a solution to the problem of taking 360° photos, Leme applied for a patent registration, a process that went on for some years.<|im_end|>
<|im_start|>assistant
Three prototypes were made and improved over one year.<|im_end|>
