I needed a cross fader that could accept an arbitrary number of signals and interpolate between them linearly two at a time, based on a 0-1 parameter.

I made [nfader~ ]. The creation argument (defaults to 2) sets the number of signal inlets from 2 to n+1, and the first (signal) inlet takes in the cross-fading parameter, a number from 0 to 1 that sweeps all the 2-n+1 inlets two by two.

Let me know if you find it useful and feel free to suggest improvements!