In this paper we show how to construct in 2 rounds a line-rigid point placement graph of size 4n/3+O(1) from small graphs called 6:6 jewels, an extension of the 4:4 jewel of [3]. This improves a result reported in [2] that uses 5-cycles. More significantly, we improve their lower bound on 2-round algorithms from 17n/16 to 14n/13.
Md. Shafiul Alam, Asish Mukhopadhyay