As described in the charlieplexing article
a specific wiring is needed to get the right effect. First Arduino pin goes to all the – pins of the LEDS on the first row, the + pins of these LEDs go to Arduino pin 2, 3, 4 etc. The second Arduino pin goes to all the – pins of the LEDS on the second row, the + pins of these LEDs go to Arduino pin 1, 3, 4 etc. And so on for all the other pins.
First add the nine current limiting resistors at the pins of the Arduino. In the software I gave them a value of 100 Ohm, but in reality, 10 Ohm or even no resistor is preferred. This is because each LED will flash only very shortly, so it isn’t at much risk for burning up.
The work in 123D is very tedious, so after the resistors start with duplicating a whole lot of LEDs in a grid. I started with red LEDs, but later on I found that the blinking of green was more visible in the software, so I changed them all.
With the leds in place, start wiring. This needs to be done very neatly, or else you will lose track of everything. I started with all the direct connections of each resistor horizontally, followed by the connections vertically.
With this done, we can work on the code!