  We introduce a new class of autoequivalences that act on the derived
categories of certain vector bundles over Grassmannians. These autoequivalences
arise from Grassmannian flops: they generalize Seidel-Thomas spherical twists,
which can be seen as arising from standard flops. We first give a simple
algebraic construction, which is well-suited to explicit computations. We then
give a geometric construction using spherical functors which we prove is
equivalent.
