A recent article by Wu and colleagues explores interesting ways to subdivide a rhombic infill to strengthen objects, for instance using a finite element simulation to subdivide weak areas in priority. This increases the density of the structures locally to obtain stronger parts.
Beside their good properties (self supporting and mechanical strength), rhombic infills are also very efficient to generate and print. Our web based slicer, SliceCrafter, includes an improved rhombic infill that prints very fast because it only uses 45 degree angled print paths (an idea suggested by IceSL user Maze Mietner). Try it out!