Victorian Goblet face illusion

I saw a similar thing to this in a 3D printing forum but as the designer did not answer any requests to share the STL file, I thought that I would have a go myself.

This is a replica of a Victorian goblet with an external profile which resembles that of a face - and as it is symmetrical, it is the same face on each side! My limited research suggests that similar goblets were made like this with the profile of Queen Victoria's face on one side and Prince Albert's on the other - my design skills are not good enough for that sort of detail!

Print Settings

Printer Brand:

RepRap

Printer:

Mendel90

Rafts:

No

Supports:

No

Resolution:

0.3mm (0.2mm would probably give a better result)

Infill:

20% - could be less

Notes:

I tried printing this as a spiralised vase using a couple of open source slicer programs but the angles, particularly at the bottom of the shape, are way too shallow. I also tried slicing as a "normal" thing then as a vase and tried to merge the two GCode files together - no success but I would think that it IS possible to do this in order to save plastic and maybe avoid any marks at layer boundaries.

I used a 0.3mm layer height setting in order to get the print done reasonably quickly but as is usual, better results could probably be obtained with a smaller layer height.