3 pins - six LEDs?

[Jeff Haas]

I was looking at a Velleman kit, the MK173, which is a variation of the "Knight Rider" effect. What's interesting to me is that it uses three pins to control six LEDs. What's this technique?

Original is in this PDF: http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk173.pdf

I can see how LEDs 1, 2 and 3 go on when the pin goes high. But how do LEDs 4, 5, and 6 go on?

 

[Technical]

Search 'charlieplex' within this forum.
Remember each of the 3 pins can go high or low....3 pins gives 8 possible combinations. Exclude all high or all low, and you end up with 6.

 

[Jeff Haas]

Thanks for the quick reply.