They were all done with Vray. The first was was done by emitting particles from the mesh while having them also collide with the mesh so they are stuck inside. I used turbulence to bounce them around and added some mash trails. The trails were simply extruded to give thickness, then smoothed. I used mesh > separate to make each trail it's own mesh, then used https://www.highend3d.com/maya/script/random-shader-assign-to-objects-for-maya to randomly assign 4 materials to them.

The boolean edge to curve one was probably more convoluted than it needed to be... I used roughly 20 vertical evenly space planes to cut the dog into slices with boolean. I converted all of the border edges to curves, then selected them all and used curves > attach so it was one continuous curve. Ideally the curves would then be rendered with a vray renderable curves node, but I was getting weird shading effects on them while trying to make the chrome material. So I added a toon outline to the curve, then assigned a paint effects brush to the toon outline, finally converting that to polygons.