  A sub-problem of the open problem of finding an explicit bijection between
alternating sign matrices and totally symmetric self-complementary plane
partitions consists in finding an explicit bijection between so-called $(n,k)$
Gog trapezoids and $(n,k)$ Magog trapezoids. A quite involved bijection was
found by Biane and Cheballah in the case $k=2$. We give here a simpler
bijection for this case.
