loaded crazycraig's remix of nihil's articulated shark into fusion360 and cleaned up the top face- removing the grooves that were in first and second segments-
edit- I see that ppardee (https://www.thingiverse.com/thing:2766851) took the same steps to clean up the grooves on nihil's original and his slices properly in simplify3d, so he beat me to the punch. the only addition my version adds over his is the thickening of the sides of the last segment before the tail for added strength.
... 4 hours later- noticed one segment was not completely flat on the bottom, so fixed that.. and while I was at it I made the sides on the segment that connects to the tail a little thicker so they will be less prone to breaking.
3/6/18- I have been printing these at 120% and they have been coming out great- the green one in the photos above is an example.
sliced in simplify3d with both external and internal thin wall type set to perimeters only- with the other values for these two properties, the slicer was leaving gaps at the thinnest section of the joints.