> radioactive atoms decay rather than reassemble<p>Under appropriate conditions of temperature they can "reassemble".<p>> Omelets don’t transform back to unbroken eggs<p>Well, mud can settle out of muddy water instead of having the water dissolve the mud.<p>And in principle if stir coffee long enough, then the cream will return as close as we please to where it was when we first poured the cream into the coffee -- this is Poincare mathematics based on ergodic theory.<p>For the coffee and cream, in simple terms, think of the positions of the cream particles in the coffee. After some stirring, first-cut, all of the possible positions are equally likely. But a huge fraction of the positions look essentially the same and, in total, are very common. There are many fewer positions that look distinctive. So, if we start with the cream in a distinctive position, say, just after pouring it in and stir, then soon we will likely have one of the positions that look the same, that is, <i>mixed in</i>. Net, time does not have a direction or <i>arrow</i> here.