// "positions" = array of FENs to detect infinite loops. Example:
// r1q1k2r/p1Pb1ppp/5n2/1f1p4/AV5P/P1eDP3/3B1PP1/R3K1NR,
// Bxd2 Bxc3 Bxb4 Bxc3 Bxb4 etc.
// "positions" = array of FENs to detect infinite loops. Example:
// r1q1k2r/p1Pb1ppp/5n2/1f1p4/AV5P/P1eDP3/3B1PP1/R3K1NR,
// Bxd2 Bxc3 Bxb4 Bxc3 Bxb4 etc.