One way this might be done is to place a grid of wires behind them and induce a magnetic field where the wires cross. The spheres at the intersections would then rotate.

方法之一，有可能是在其背后建立一网格线和在线经过的地方引入磁场，在这地方的微珠就可以旋转了。

youdao

Go behind the hotel, knock at the correct door, walk through the hotel's busy kitchens, cross a courtyard, then knock at another locked door.

来到酒店后面，敲对某一扇门，走过酒店忙碌的厨房，穿过一个院子，再敲另一扇门。

youdao

We use OpenCV as a base for all of our cross platform computer vision / image processing algorithms and video capture support, and Mono is the main engine behind robotSuite.

我们使用OpenCV作为我们所有的跨平台的计算机视觉/图像处理算法和视频捕捉支持的基础，Mono是robotSuite后面的主要引擎 。

youdao

Generally, fixed- income is generally behind cross-border flows in the forms of reserve flows and safe haven moves, yet equity flows have played a role this time.

FORBES: Ignore Bernanke's QE And Focus On Equity Flows: The U.S. Dollar Is Getting Stronger

Just behind Kings Cross station lies St Pancras cemetery, home to St Pancras Old Church, which has been a site of Christian worship since the 4th Century.

BBC: In search of London's lost rivers

Booth, once inside Ford's, wanted to cross behind the stage all the way to the other side of the building, where a small door led to a narrow passageway that ran west to Tenth Street and the front of the theatre.

NPR: Excerpt: 'Manhunt'