[ 20/21 -2/21 ] [ 22/21 -4/7 ] 
4/7 |-> 20/21
2/21 |-> 22/21
10/21 |-> 22/21
-10/21 |-> 20/21
f(z) = -147/80*z^3 + 31/60*z + 1
*
[ -6/7 26/7 ] [ 20/7 -26/7 ] 
4/7 |-> -6/7
-4/7 |-> 20/7
30/7 |-> 20/7
-30/7 |-> -6/7
f(z) = 49/240*z^3 - 199/60*z + 1
*
[ 4/17 26/17 ] [ 30/17 -26/17 ] 
-6/17 |-> 4/17
6/17 |-> 30/17
20/17 |-> 30/17
-20/17 |-> 4/17
-14/17 | 0.15706945519975658577364143426512828823 | 0.024849741026360375333146745646596232308
f(z) = -289/240*z^3 + 139/60*z + 1
*
TOTAL: 3