Format 2.1
# Borromean rings group branched of order 4
words { a A b B c C d D e E f  F}
inverses {case_change}
rels {  a*a*a*a
        b*b*b*b
        c*c*c*c
        d*d*d*d
        e*e*e*e
        f*f*f*f
        a*b*A*e
        b*c*B*f
        c*d*C*a
        d*e*D*b
        e*f*E*c
        f*a*F*d
        }

