  Arbitrary Pattern formation ($\mathcal{APF}$) by a swarm of mobile robots is
a widely studied problem in the literature. Many works regarding
$\mathcal{APF}$ have been proposed on plane and infinite grid by point robots.
But in practical application, it is impossible to design point robots. In
\cite{BoseAKS20}, the robots are assumed opaque fat robots but the environment
is plane. To the best of our knowledge, no work till now ever considered the
$\mathcal{APF}$ problem assuming opaque fat robots on infinite grid where
movements are restricted. In this paper, we have provided a collisionless
distributed algorithm and solved $\mathcal{APF}$ using 9 colors.
