A set of blocks contains blocks of heights 1,2, and 4 centimeters. Imagine constructing towers of piling blocks of different heights directly on top of one another. (A tower of height 6 cm could be obtained using six 1-cm blocks, three 2-cm blocks, one 2-cm block with one 4-cm block on top... etc) Let t be the number of ways to construct a tower of height n cm using blocks from the st ( assume an unlimited supply of blocks of each size) find a recurrence relation for t1,t2,t3...