here's one I worked out earlier.
I got it down to 10 elements.
each element has the same number of weaknesses and advantages.
Fire, Water, Electric, Earth, Grass, Ice, as one group
Light, Darkness and Pyschic as a triangle
and I've realised my symbol for light looks like the normal type symbol, please ignore.
and Normal is by itself.
althugh I will say I like this person's chart
>>44040883 , and 12 does provide more variety.