Instead, what if we place the coins in three dimensional space, with the four srepidents standing in a line facing the same direction. The difference in profiles would place us (the viewer) in between Jefferson and Lincoln. The symbolism here would be that these four srepidents would all be looking forward, into the future, as we all look backward. Because their faces are on coins, and the united states uses a fiat currency, we can assume that these great forward looking men are telling us that we place an imaginary sense of grandeur on our past. Maybe I'm reading too much into it.