So, what you do is you set up a couple of displays, one where the block is stopped, the other one where you take this away with a trap door and it keeps going.
所以，你可以设计几个演示，一个是木块被挡住了，另一个是用活门把木块挪开，使得屏板继续上升。
2
We purposely picked a home that was ablock away from the train stop and has bus lines that are within feet of our front door. We can get anywhere in this city easily.