2. fluorescent light emitted is gauged
    & used to decide size/shape of cells

3. Cells passed through nozzle & form
    droplets (one cell per drop); if drops
    given negative charge or hold a
    magnetic bead they can be culled

4. droplets with no charge
    droplets with lesser charge
    droplets with more charge
             separated in electric field
             in milliseconds

can do up to 10 million drops per hour