Elongated molecules are stretched across a substrate by controlled fluid flow. The systems and methods can include creating one or more execution blocks, each associated with a sequence of screen events of a user interface, from a function stored in a script; storing the one or more execution blocks as handlers; and executing the one or more handlers independently from each other, when the associated sequence of screen events for the handler is detected in network traffic. When focusing onto a high density optical disk, adjacent tracks do not see the canceled, circularly-polarized portions of the beam, but instead, only see the smaller, plane-polarized portion in the center of the beam. The power from both the motor and first engine can be selectively combined for varied conditions of operation of the vehicle. Any executable function can be designated by the user as the object of a task.