17. Rook can perpetually chases protected cannon. If the cannon is
protected in one move and not in another move, this chase is still
allowed. (See examples in Diagram 29, 30, and 31.)

Diagram 29: Red moves first

R1=2 c8=9
R2=1 c9=8
R1=2 c8=9
R2=1 c9=8
R1=2 ...

Explanation:

In Diagram 29 and 30 the Red rook perpetually chases the protected
cannon. This is a draw.

Diagram 30: Red moves first

R4=3 c7=3
R3=7 c3=7
R7=3 c7=3
R3=7 c3=7
R7=3 ...

Explanation:

In Diagram 29 and 30 the Red rook perpetually chases the protected
cannon. This is a draw.

Diagram 31: Red moves first
R2=1 c9=8
R1=2 c8=9
R2=1 c9=8
R1=2 c8=9
R2=1 ...

Explanation:

Black cannon's perpetually threatening to checkmate is allowed;
Red rook's perpetually chasing the once protected and once
unprotected Black cannon is also allowed. This is a draw.