Super jackstraws and super waterwheels

We construct various new BPS states of D-branes preserving 8 supersymmetries.These include super Jackstraws (a bunch of scattered D- or (p,q)-stringspreserving supersymmetries), and super waterwheels (a number of D2-branesintersecting at generic angles on parallel lines while preservingsupersymmetries). Super D-Jackstraws are scattered in various dimensions butare dynamical with all their intersections following a common null direction.Meanwhile, super (p,q)-Jackstraws form a planar static configuration. We showthat the SO(2) subgroup of SL(2,R), the group of classical S-dualitytransformations in IIB theory, can be used to generate this latterconfiguration of variously charged (p,q)-strings intersecting at variousangles. The waterwheel configuration of D2-branes preserves 8 supersymmetriesas long as the `critical' Born-Infeld electric fields are along the commondirection.Comment: 23 pages, 10 figure