Format 2.1
# Borromean rings group
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*a*c*d
        D*e*d*b
        E*f*e*c
        F*d*f*a
        }

