  Measurement-based quantum computing (MBQC) is a model of quantum computation
where quantum information is coherently processed by means of projective
measurements on highly entangled states. Following the introduction of MBQC,
cluster states have been studied extensively both from the theoretical and
experimental point of view. Indeed, the study of MBQC was catalysed by the
realisation that cluster states are universal for MBQC with (X,Y)-plane and Z
measurements. Here we examine the question of whether the requirement for Z
measurements can be dropped while maintaining universality. We answer this
question in the affirmative by showing that universality is possible in this
scenario.
