  An $n$-correct node set $\mathcal{X}$ is called $GC_n$ set if the fundamental
polynomial of each node is a product of $n$ linear factors. In 1982 Gasca and
Maeztu conjectured that for every $GC_n$ set there is a line passing through
$n+1$ of its nodes.So far, this conjecture has been confirmed only for $n\le
5.$ The case $n = 4,$ was first proved by J. R. Bush in 1990. Several other
proofs have been published since then. For the case $n=5$ there is only one
proof: by H. Hakopian, K. Jetter and G. Zimmermann (Numer Math $127,685-713,
2014$). Here we present a second, much shorter and easier proof.
