I thought maybe the people in this group would find this interesting. I have been contemplating a retractable water system for my rodent grow out racks (large cement mixing tubs which are too deep for the little ones to access water from the top. Well, I was building legos with the kids one evening an had an idea. Here is the first prototype. With the exception of the water valves and metal washers, it is built entirely from legos. What do ya'll think?