  Recently, it has been shown that every recursively enumerable language can be
generated by a scattered context grammar with no more than three nonterminals.
However, in that construction, the maximal number of nonterminals
simultaneously rewritten during a derivation step depends on many factors, such
as the cardinality of the alphabet of the generated language and the structure
of the generated language itself. This paper improves the result by showing
that the maximal number of nonterminals simultaneously rewritten during any
derivation step can be limited by a small constant regardless of other factors.
