The next step was to figure out how to circulate the pills from something that could connect to the
center shaft and would easily rotate the pills without damaging them. Model airplane propellers were used
because they had angles on them and already had a center hole with relatively soft plastic. We found an
electrostatic brush at Target that was cut into strips and epoxy was used to attach the brush strips to the
propellers, see figure 8. The electrostatic brush featured rubber 1/8 in bristles that were rough enough to pull a
jammed pill out of the slide most of the time, but was soft enough not to break or damage the pills.