These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.00 s (backtrack: 0/20).

[ebuild  N     ] media-gfx/tachyon-0.99.5::gentoo  USE="jpeg opengl openmp png threads -doc -examples -mpi" 1136 KiB

Total: 1 package (1 new), Size of downloads: 1136 KiB