(a) Does there exist a magic hexagon of order 2 ? That is, is it possible to arrange the numbers $1,2, \ldots, 7$ in the following hexagonal array so that all of the nine "line" sums (the sum of the numbers in the hexagonal boxes penetrated by a line through midpoints of opposite sides) are the same?
(b) " Construct a magic hexagon of order 3 ; that is, arrange the integers $1,2, \ldots, 19$ in a hexagonal array (three integers on a side) in such a way that all of the fifteen "line" sums are the same (namely, 38 ).