It is a pentagonal prism
effective no. of A atoms = (8*1/8)+(4*1/2)=3 effective no. of B atoms = (12*1/4)+1=4 therefore formula of the solid = A3B4
That's the principle behind RADAR (Radio Detection And Ranging). A brief, high-powerpulse of radio is transmitted, then the transmitter goes silent, and the receiver listens forthe small bit of signal reflected back from any solid object. The size and distance of thesolid object are calculated from the strength and time-lag of the reflected signal.