I think they are using these:-
What are the readings one get? If I press att spot 1, I get say 7 kOhm. If I press at spot 2, I get say 3 kOhm. If I press at spot 1 and spot 2, what do I get?
I'm building an ukulele and I'm thinking of either having short strips of softpots on each fret or four long strips like the strings. In either case the player might press two spots on one softpot at the same time.