  Programmable Matter (PM) has been widely investigated in recent years. It
refers to some kind of matter with the ability to change its physical
properties (e.g., shape or color) in a programmable way. One reference model is
certainly Amoebot, with its recent canonical version (DISC 2021). Along this
line, with the aim of simplification and to better address concurrency, the
SILBOT model has been introduced (AAMAS 2020), which heavily reduces the
available capabilities of the particles composing the PM. In SILBOT, in fact,
particles are asynchronous, without any direct means of communication (silent)
and without memory of past events (oblivious). Within SILBOT, we consider the
Line Formation primitive in which particles are required to end up in a
configuration where they are all aligned and connected. We propose a simple and
elegant distributed algorithm - optimal in terms of number of movements, along
with its correctness proof.
