  Cells are modeled with spherical grains connected each other. Each cell can
shrink and swell by transporting its fluid content to other connected neighbor
while still maintaining its density at constant value. As a spherical part of a
cell swells it gains more pressure from its surrounding, while shrink state
gains less pressure. Pressure difference between these two or more parts of
cell will create motion force for the cell. For simplicity, cell is considered
to have same density as its environment fluid and connections between parts of
cell are virtually accommodated by a spring force. This model is also limited
to 2-d case. Influence of parameters to cell motion will be presented. One
grain cell shows no motion, while two and more grains cell can perform a
motion.
