4 Tremolo repeats can be constructed for short tremolos (total duration smaller than 1/4) too. Only some of the beams are connected to the stems.
9 \context Staff \relative c' {
10 \repeat "tremolo" 2 { c32 e32 }
12 \repeat "tremolo" 2 { c32 e32 }
14 \layout { raggedright = ##t }