The object was able to move easily over very challenging terrain, such as piles of sand or a field of ball bearings. Using the same principles, the researchers could build different shapes: ...

Physics has laws, and so does chemistry. What about biology? Here are a couple of suggestions to get you thinking about whether or not there are biological laws of nature.

In other disciplines (archeology, geology, architecture) it is customary to place an object, such as a coin, a scale or human beings, close to the object of focus, to provide relative dimensions.