Simple project in Java

Diffusion A simple model of diffusion and pattern formation can be made as follows. Imagine a grid of say, 400 x 400 points upon which are scatters, say 3000 atoms randomly. Now have an atom enter the grid from some random point on the edge, and make a rule that the atom will move around the grid until either it leaves the grid, or else it comes to a point which is immediately next to point containing an atom, in which case it will stick to that point. HAve the motion of the atom "almost" random - if it enters from the left, say, have it preferentially move to the right (say, with probability 40%), but it could also move up or down (say, with probabilities of 25% each) or back to the left (with probability, say 10%). Now have another atom enter the grid, and follow the same rule, and so on. Write a program which will take command-line options indicating the size (in pixels) of the (square) grid to consider, the initial number of atoms to scatter randomly about the grid, and the number of atoms that enter the grid, and which will then produce a png (or jpeg) image of the results, using the gd library. Include in your output 4-6 images representing an interesting range of parameters, This can be done in C++, or java preferably I need this right away(24 hours), when can it be done?