Nireas is a theme manager for Pharo 4
to install Nireas you need to have Pharo 4, then open Configuration Browser from World Menu > Tools and install the stable version.
Then open World menu and go to System > Settings and in Appearance choose the Nireas theme. Then open World menu again and go to Ephestos > Nireas.
Test Nireas on a clean image because it is experimental. Please report any bugs.