An air removal device removes air from blood flowing in a perfusion system. For example, a receiver which does not include a fax modem may receive faxes which are transmitted to a station. When determining the consistency, entries of a distance matrix, indicative of distance differences of 3D components between different views for a corresponding segment k when projected to the predefined view for each segment k, are compared with entries of a threshold matrix. The fasteners consist of a key and a screw that fits within the key. An electronic circuit controls three or more analog outputs in response to a single analog input, each of the analog outputs controlling a different one of the light sources.