We use a semigroup-theoretic construction by Peter Higgins in order to produce, for each even n, an n-state and 3-letter synchronizing automaton with the following two features: 1) all its input letters act as idempotent selfmaps of rank n 2 ; 2) its reset threshold is asymptotically equal to n 2 2 . * Supported by the Ministry of Science and Higher Education of the Russian Federation, project no. 1.580.2016, and the Competitiveness Enhancement Program of Ural Federal University.