Over/under extrusion?

Just trying to figure out what is going on with the top of this calibration print.

http://imgur.com/gallery/wyUpI/new

What material are you using? And what speed are you printing at? It looks like an overheating issue to me, with maybe a touch of over-extrusion (although the bottom of your print looks ok). Which slicing software are you using? The straight lines looks a little rounded near the corners making me wonder if your print speed is a bit too high.

ABS at 260/110. I also tried it at 240 and it looks about exactly the same, and 225 (which had too little layer adhesion).
Printing at 60mm/s with Outline Underspeed of 40%, Solid Underfill Underspeed of 80%.

Unfortunately all the images of the top of the print are out of focus. From the image of the base I would say that your nozzle is probably too far away from the print bed, the lines of plastic should be joined up as well so there could be an under extrusion issue but don't look to this until you check your nozzle height.

As to the top, the images are a bit out of focus to tell properly but it could be that it's collapsing in on itself as the filament does not have time to cool before the next layer is added. What are your fan settings? Although you have to be careful with using a fan for ABS as it enhances warping. See if you can change the fan settings and make it trigger when the layer print time is very small so that it only turns on at the top layer. This is one possible explanation.

what's your infill % set on ?
Looks like bridging with ony 1 or 2 layers to me. And yep fan blowing on print area should fix that.
The edges of the cubes look fine.

I agree with what everyone has said above. My stongest feeling is that there is overextrusion, I'm guessing that these were printed solid or close to it (given the small size of the cubes and amount of perimeters). Seeing that top cube most deformed is what makes me say that the most, because at the end of your print all the over extrusion happening in the bottom of the print builds up and spills out of the top cube's perimeters.

Also the top is likely deformed because the layers are so small that the plastic doesn't have time to fully solidify before new layers are added. In some slicers, there are settings to slow down the print above layer X or during the last X layers of the print, which might also help.