u know it is lil bit based on the CNC machines we read in 7th sem... it has two rails, the command is fed in 3 axes- x, y and z... u have to create the wall at a different location and the tools mounted on the beam will place it on the contour fed into the system and cements are released from high pressure cement mixing machines.. but it has a limitation that it can only build limited storey buildings coz the height of the cranes are limited... everything is pre-manufactured here and this machine is only used to pile them... gr8 innovation...