They brought the prototype out only once, late at night, to test it on the color projection television in one of the conference rooms.

这台机器只被他们带出过房间回，是天的深夜，他们将它带到了间议室，连接上彩色投影电视进行。

So to sum up, on the surface, the dot product is a very useful geometric tool for understanding projections and for testing whether or not vectors tend to point in the same direction.

上所述 表面上 点积是个非常有用的几何工具用于理解投影和向量是否指向同个方向。