Three fixed points in 3D space are each connected to a mobile fourth point with three elastic bands. The elastic bands are slack when shorter than their rest length, and they pull according to Hooke's law (simple linear, constant). The challenge is to find where the fourth point is when the pull vectors from all three elastics add to zero. In other words: where would the mobile fourth point come to rest? There will obviously be solutions involving iterative approximation, but is there a direct way to determine the location? It is easy if the elastics pull from length zero onwards, because then you can find the fourth point by a weighted average of the fixed three. Does the simple addition of the elastic slack-zone suddenly make this a difficult problem?