  In recent years, expansion-based techniques have been shown to be very
powerful in theory and practice for solving quantified Boolean formulas (QBF),
the extension of propositional formulas with existential and universal
quantifiers over Boolean variables. Such approaches partially expand one type
of variable (either existential or universal) and pass the obtained formula to
a SAT solver for deciding the QBF. State-of-the-art expansion-based solvers
process the given formula quantifier-block wise and recursively apply expansion
until a solution is found.
  In this paper, we present a novel algorithm for expansion-based QBF solving
that deals with the whole quantifier prefix at once. Hence recursive
applications of the expansion principle are avoided. Experiments indicate that
the performance of our simple approach is comparable with the state of the art
of QBF solving, especially in combination with other solving techniques.
