A squarefree term not occurring in the Leech sequence

Let $$\begin{array}{c}\bar{A}=ABCBACBCABCBA,\\ \bar{B}=BCACBACABCACB,\\ \bar{C}=CABACBABCABAC\mathrm{.}\end{array}$$ The Leech sequence $L$ is the squarefree sequence obtained as the limit of the palindromes $$A,\bar{A},\overline{\stackrel{‾}{A}},\dots \mathrm{.}$$ In order to specify a certain class of pseudorecursive varieties of semigroups, it is helpful to have a squarefree term in 3 variables such that no substitution instance occurs as a subterm of $L$. We show that ${\kappa }_1=abacbcabac$ is such a term. Except for one situation, the doubly-linked term $\kappa_2 = aba\ cbc\ aba$ will serve, and we focus on it.