YES After renaming modulo { a->0, b->1, c->2, d->3, e->4 }, it remains to prove termination of the 8-rule system { 0 0 -> 1 1 1 , 0 -> 2 3 , 1 1 -> 2 2 2 , 2 2 -> 3 3 3 , 4 3 -> 0 1 2 3 4 , 1 -> 3 3 , 4 2 -> 1 0 0 4 , 2 3 3 -> 0 } Applying sparse 2-untiling [Hofbauer/Geser/Waldmann, FSCD 2019]. After renaming modulo { 0->0, 1->1, 2->2, 3->3 }, it remains to prove termination of the 6-rule system { 0 0 -> 1 1 1 , 0 -> 2 3 , 1 1 -> 2 2 2 , 2 2 -> 3 3 3 , 1 -> 3 3 , 2 3 3 -> 0 } The system was filtered by the following matrix interpretation of type E_J with J = {1,...,2} and dimension 2: 0 is interpreted by / \ | 1 80 | | 0 1 | \ / 1 is interpreted by / \ | 1 53 | | 0 1 | \ / 2 is interpreted by / \ | 1 35 | | 0 1 | \ / 3 is interpreted by / \ | 1 23 | | 0 1 | \ / After renaming modulo { }, it remains to prove termination of the 0-rule system { } The system is trivially terminating.