This idea was an amazing design when I first stumbled over it. I modified the design because I wasn't happy with his results. He created a 4 mixer input and 4x multiple. The problem I found was, that it wasn't multiplying what came in. So if you have a quntized input, the output would be totally different. So I tested a few other resisters and circuits and came up with the following design. It's still not perfect, but it repeats the input more or less over 2-3 octaves, which I think is quite good for such a simple design. And as this is a tripple design, the inputs are normalled and I get a little more out of it. And... as the signal only needs to be buffered I relinquished to add unnescessary curcuitory.
The design here is only one "channel". Repeat it as many times as nescessary ;)