Ponderable 4.1.2

(1) There are 15 tiles and a hole, a move can correspond to a permutation of $\frac{\mathrm{\mathbb{Z}}}{\mathrm{16}\mathrm{\mathbb{Z}}}$.

(2) Of course.

(3) Yes, just perform the reverse moves.

(4) Yes, two moves lead to another move and not to an illegal move.

Maison