Some simple structure of maximally four-qubit state is presented. Using stochastic local operations and classical communication (SLOCC) invariants, it is can be shown those simple structure of maximally four-qubit state is SLOCC equivalent to four-qubit \c{hi} state.
@article{arxiv.1401.6622,
title = {Simple forms of SLOCC equivalent four-qubit \c{hi} state},
author = {Xin-Wei Zha and Jian-Xia Qi and Yun-Guang Zhang},
journal= {arXiv preprint arXiv:1401.6622},
year = {2016}
}