The researchers said they had not yet built a working prototype to test the design.

They designed and built a prototype of the 12-bit version.

Helped by two of his sons, he built a prototype.

He went to his workshop, built a prototype, and then could not market it.

He built prototypes, and the first was operating in 1973.

The next stage, of course is to build prototypes for further testing and development.

Over the next year, Microsoft built more than 85 prototypes.

The team built a working prototype but decided that the system was too unstable and expensive.

I also can't figure out how he could've built a new prototype so fast.

He built several prototypes in the 1950s, but no branch of the military was interested.