Here are a sphere, heart, and cube made from a polyhedron containing 380 hexagonal and 12 pentgonal faces - a polyhedron related to a 780 atom Buckyball. The same edges, (bonds), are used for all three objects. The polyhedron vertices form an approximate sphere which is mapped to a cube

http://stackoverflow.com/questions/2656899/mapping-a-sphere-to-a-cube

and to a heart. The heart is made by sending the x,y,z coordinates of the sphere to x, y+fxabs(x), fzz where fx and fz are adjustable parameters. The method was suggested by DJ Moews.

OpenSCAD code is included.

Versions of the three objects are provided with and without support.

The animate command in OpenSCAD can be used to generate a movie of the change from a sphere to a heart. Instructions are included in the OpenSCAD code.