Does any one know how does one drive 36 LED segments with only 7 pins? What is this technique called?
Maybe you're thinking of Charlieplexing - Wikipedia ?
It's called "using a display controller IC". Maybe even fewer pins. 
But you didn't say whether you can control the wiring design or whether the wiring is pre-existing and fixed.
I don't know how your particular hardware works, but with I have 48 individually-addressable LEDs controlled serially from 3 output pins (data, clock, and latch).
There is a common-popular one-wire LED interface that can address an almost unlimited number of LEDs.
The whole internet is also serial (one bit at a time).
with enough amount of 74hc595(596) i can drive many more then 36 LEDs with 5 pins.
MAX7912 64 LEDs .
Hi, @killzone_kid
What is your project?
Thanks.. Tom.. 
This must be it, thanks! I will try to poke the LED display with some voltages to different pins later to confirm this is the case. 7 pins - 42 LEDs, strangely both displays had 36 LEDs, maybe just a coincidence. One of them for example:
That display looks as if it would have seven pins on the other side as well! 
they are connected in the parallel dimension
yep, i have two, one is sacrificed in the name of curiosity. Here is another one let’s see if you can figure this one out
You’re good!
So yes, this is Charlieplexing. So is there an I2C controller for this? Don’t really wanna waste 7 IOs on this
Going to use ATTiny84 over serial, and why not, I had ATTiny85 programmer, it only took another circuit and a few wires to adapt it for 84
Nice!
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