self -constructing Ice castle

It is possible to make a self constructing Ice castle using nethercap (which freezes water)

set up mesecons pistons pointing up, below the water line. surround them with leaves, to prevent Ice from forming but allow water to flow in, leaving the space directly above the piston clear. This will allow water to flow into the space, where the nethercap will freeze it. Then the piston activates, pushing the ice up and out of the way. It is possible to make a large ice structure easily that way.