It looks cool, but I suspect you'll get very poor flow where you need it the most--at the base.
At a glance, it looks like water feeds in on several 'ramps' in parallel at the bottom, and goes merrily along to the top, where it exits the ramps.
But it won't work that way. The water on the bottom ramp has to merge with the water entering the second, and they both have to merge with the water coming in on the third...and since water is incompressible, it has to move faster to move a greater volume of water.
I don't see any way of balancing it, either.
For an analogy, think of the parking garages in big cities, and how much of a pain in the butt it is for everyone on the different levels to merge onto the spiral ramp.
Cool looking design, though.
<edit>Also, since water is a fluid, it's going to take the easiest path. The path with the least resistance due to direction changes/centrifugal force, etc. is the one where the water enters the highest input, and exits at the lowest output.
The path with the least resistance due to friction between the water and the block, and also between the water and itself also happens to be that same shortest path.
In effect, it's basically only going to touch the middle of the block, and leave stagnant hot water at the base.
Now convection will counteract this, but not by much, I suspect.
</edit>