A 2 level system has E1 = 0 J and E2= 1x10^-20 as its two energy levels. There are four particles which are distributed within these 2 energy levels, which are marked a, b, c, d. For each energy state of the system, calculate the number of microstates, W, that have this energy. Make sketches of these microstates. Calculate the corresponding entropy for each state.