restart;
Arithmetisation of the Peano Curve
Definition of the operators P0 bis P8 (on page 58) - compare Function peano in Section 4.5:
P[0] := (x,y) -> (x/3,y/3);
P[1] := (x,y) -> (1/3-x/3,1/3+y/3);
P[2] := (x,y) -> (x/3, y/3+2/3);
P[3] := (x,y) -> (1/3+x/3, 1-y/3);
P[4] := (x,y) -> (2/3-x/3,2/3-y/3);
P[5] := (x,y) -> (1/3+x/3,1/3-y/3);
P[6] := (x,y) -> (2/3+x/3, y/3);
P[7] := (x,y) -> (1-x/3, 1/3+y/3);
P[8] := (x,y) -> (2/3+x/3, 2/3+y/3);