Each of the small 12 identical blocks has dimensions 4 by 5 by 7 inches.
Together they form a larger block of:
width w=5 in length l = 7 in+7 in+7 in = 21 in height h = 4 in + 4 in + 4 in + 4 in=16 in
The total area of the block is: (front face+back face)+("floor" face + "ceiling" face) + 2 side faces = 16 * 21 + 16*21 + 5*21+ 5*21 + 5*16+5*16 (square inches) = 336+336+105+105+80+80 (square inches)
