One had extreme difficulty riding a bicycle, and on the second day he showed up with a tricycle. One other student tried it as well.
Results were not on a par with a two-wheeler, but it solved the guy's problem of getting his own data to work with. He now understands the process.
![](http://static.flickr.com/41/96806354_c4490fc0cf.jpg)
Luis J. Berrios Montes with his tricycle