@rbathoorn this integrates your code, with a few tweaks:

• changed the base tooling to be more modern (we now have unit tests running in CI!)
• the new projections are listed in the README
• edited the default angle, scale, translate parameters so that the maps would fit in the usual 960x500 frame
• modified the default rotate
• tweaked the implementation to more modern JavaScript

I wonder if we could shorten the names of the two new projections. The complete (& accurate) geometric description is a bit long.

The default aspect of the rhombic dodecahedral might need some more thought. It would be more readable with the North pole at the top?

Note that because of the new rhombic dodecahedral projection, the previously "geoDodecahedral" projection should be “pentagonal dodecahedral" :) But I don't plan to change its symbol.

Another remark is that the polyhedral/ sub-directory is now a bit inconsistent… maybe we should flatten everything since most of these projections are polyhedral?

This feels like a better default aspect:

d3.geoRhombicDodecahedral().rotate([80, 0, -Math.asin(Math.sqrt(3) / 3) * 90])

This feels like a better default aspect:

d3.geoRhombicDodecahedral().rotate([80, 0, -Math.asin(Math.sqrt(3) / 3) * 90])

Look better indeed. And the names of the functions could be shortened to something like geoRhombic and geoDeltoidal I just put in the whole names as all the previous ones also had the complete names :)