Questions on Minsky paper

1) List a few problems that serial arms display.

2) Force feedback can be used for position sensing. Minksy says "So the six-axis force measurement can serve as a tactile-position sensor over the entire surface!". So, if you touch the surface with one finger, a six-axis sensor attached to the springs supporting the surface can determine where your finger touched. Would it work if you touched the surface with two fingers at the same time?

3) What is an "escalator grip"?

4) How many degrees of freedom does a "Fourier wrist" have?