  Robotic manipulation of deformable objects gains great attention due to its
wide applications including medical surgery, home assistance, and automatic
food preparation. The ability to deform soft objects remains a great challenge
for robots due to difficulties in defining the problem mathematically. In this
paper, we address the problem of shaping a piece of dough-like deformable
material into a 2D target shape presented upfront. We use a 6 degree-of-freedom
WidowX-250 Robot Arm equipped with a rolling pin and information collected from
an RGB-D camera and a tactile sensor. We present and compare several control
policies, including a dough shrinking action, in extensive experiments across
three kinds of deformable materials and across three target dough shape sizes,
achieving the intersection over union (IoU) of 0.90. Our results show that: i)
rolling dough from the highest dough point is more efficient than from the
2D/3D dough centroid; ii) it might be better to stop the roll movement at the
current dough boundary as opposed to the target shape outline; iii) the shrink
action might be beneficial only if properly tuned with respect to the expand
action; and iv) the Play-Doh material is easier to shape to a target shape as
compared to Plasticine or Kinetic sand. Video demonstrations of our work are
available at https://youtu.be/ZzLMxuITdt4
